From ba91d7f21bca4cf29cd1b9c14eb011e9cb17ec1a Mon Sep 17 00:00:00 2001 From: qiancai Date: Tue, 16 Dec 2025 16:10:19 +0800 Subject: [PATCH 01/45] Create release-8.5.5.md --- releases/release-8.5.5.md | 116 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 releases/release-8.5.5.md diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md new file mode 100644 index 0000000000000..af1068c6da2f7 --- /dev/null +++ b/releases/release-8.5.5.md @@ -0,0 +1,116 @@ +--- +title: TiDB 8.5.5 Release Notes +summary: Learn about the features, compatibility changes, improvements, and bug fixes in TiDB 8.5.5. +--- + +# TiDB 8.5.5 Release Notes + +Release date: xx xx, 2026 + +TiDB version: 8.5.5 + +Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with-tidb) | [Production deployment](https://docs.pingcap.com/tidb/v8.5/production-deployment-using-tiup) + +## Features + +### Scalability + +* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** + + Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + + For more information, see [Documentation](link). + +### Performance + +* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** + + Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + + For more information, see [Documentation](link). + +### Reliability + +* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** + + Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + + For more information, see [Documentation](link). + +### Availability + +* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** + + Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + + For more information, see [Documentation](link). + +### SQL + +* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** + + Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + + For more information, see [Documentation](link). + +### DB operations + +* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** + + Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + + For more information, see [Documentation](link). + +### Observability + +* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** + + Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + + For more information, see [Documentation](link). + +### Security + +* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** + + Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + + For more information, see [Documentation](link). + +### Data migration + +* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** + + Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + + For more information, see [Documentation](link). + +## Compatibility changes + +### Behavior changes + +### MySQL compatibility + +### System variables + +| Variable name | Change type | Description | +|--------|------------------------------|------| +| | | | +| | | | +| | | | + +### Configuration parameters + +| Configuration file or component | Configuration parameter | Change type | Description | +| -------- | -------- | -------- | -------- | +| | | | | +| | | | | +| | | | | + +### System tables + +### Other changes + +## Improvements + +## Bug fixes \ No newline at end of file From 45da8e9f67ebe24171ed3a3524792e1e21efdead Mon Sep 17 00:00:00 2001 From: qiancai Date: Wed, 17 Dec 2025 14:09:54 +0800 Subject: [PATCH 02/45] add feature description for #56522 and #58685 --- releases/release-8.5.5.md | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index af1068c6da2f7..135597ede3cfe 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -23,6 +23,16 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Performance +* Point-in-time recovery (PITR) supports recovery from compacted log backups for faster restores [#56522](https://github.com/pingcap/tidb/issues/56522) @[YuJuncen](https://github.com/YuJuncen) + + Starting from v9.0.0, the compact log backup feature provides offline compaction capabilities, converting unstructured log backup data into structured SST files. This results in the following improvements: + + - SST files can be quickly imported into the cluster, **improving recovery performance**. + - Redundant data is removed during compaction, **reducing storage space consumption**. + - You can set longer full backup intervals while ensuring the Recovery Time Objective (RTO), **reducing the impact on applications**. + + For more information, see [documentation](/br/br-compact-log-backup.md). + * Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. @@ -55,6 +65,12 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### DB operations +* Improve the compatibility between ongoing log backup and snapshot restore [#58685](https://github.com/pingcap/tidb/issues/58685) @[BornChanger](https://github.com/BornChanger) + + Starting from v9.0.0, when a log backup task is running, if the conditions are met, you can still perform snapshot restore and allow the restored data to be properly recorded by the ongoing log backup. This enables ongoing log backups to proceed without having to stop them during the restore procedure. + + For more information, see [documentation](/br/br-pitr-manual.md#compatibility-between-ongoing-log-backup-and-snapshot-restore). + * Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. From 1f2860a8d4ff82b2de5c0a1047bb2b1f20bfb931 Mon Sep 17 00:00:00 2001 From: Ben Meadowcroft Date: Wed, 17 Dec 2025 10:32:46 -0800 Subject: [PATCH 03/45] Added descriptions for additional changes included in the release Signed-off-by: Ben Meadowcroft --- releases/release-8.5.5.md | 32 +++++++++++++++++++++++++++----- 1 file changed, 27 insertions(+), 5 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 135597ede3cfe..ce5a8955a7e44 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -25,14 +25,20 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Point-in-time recovery (PITR) supports recovery from compacted log backups for faster restores [#56522](https://github.com/pingcap/tidb/issues/56522) @[YuJuncen](https://github.com/YuJuncen) - Starting from v9.0.0, the compact log backup feature provides offline compaction capabilities, converting unstructured log backup data into structured SST files. This results in the following improvements: + Starting from v8.5.5, the log backup compaction feature provides offline compaction capabilities, converting unstructured log backup data into structured SST files. This results in the following improvements: - - SST files can be quickly imported into the cluster, **improving recovery performance**. - - Redundant data is removed during compaction, **reducing storage space consumption**. - - You can set longer full backup intervals while ensuring the Recovery Time Objective (RTO), **reducing the impact on applications**. + - **Improved recovery performance** - SST files can be more quickly imported into the cluster. + - **Reduced storage space consumption** - redundant data is removed during compaction. + - **Reduced impact on applications** - RPOs can be amintained with less frequent full snapshot-based backups. For more information, see [documentation](/br/br-compact-log-backup.md). +* Accelerated recovery of system tables from backups [#58757](https://github.com/pingcap/tidb/issues/58757) @[Leavrth](https://github.com/Leavrth) **tw@xxx** + + When restoring system tables from a backup, BR now introduces a new `--fast-load-sys-tables` parameter to use physical restoration instead of logical restoration. This option completely overwrites/replaces the existing tables, instead of restoring into them, for faster restoration for large scale deployments. + + For more information, see [Documentation](/br/br-snapshot-guide.md#restore-tables-in-the-mysql-schema). + * Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. @@ -41,6 +47,10 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Reliability +* Improved store scheduling in presence of network jitter [#9359](https://github.com/tikv/pd/issues/9359) @[okJiang](https://github.com/okJiang) **tw@xxx** + + Provides a network status feedback mechanism to PD to avoid scheduling the leaders back to a problematic node (experiencing network jitter) after the leaders had been transferred off the node by TiKVs detection of the network jitter. + * Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. @@ -49,6 +59,12 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Availability +* Introduce Client Circuit Breaker Pettern for PD [#8678](https://github.com/tikv/pd/issues/8678) @[Tema](https://github.com/Tema) **tw@xxx** + + To protect the PD leader from overloading due to retry storms or similar feedback loops, a circuit breaker pattern is introduced to limit incoming traffic (when a threshold of errors is reached) to enable the system to stabilize. The `tidb_cb_pd_metadata_error_rate_threshold_ratio` system variable is used to control the application of the circuit breaker. + + For more information, see [Documentation](/system-variables.md#tidb_cb_pd_metadata_error_rate_threshold_ratio-new-in-v900). + * Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. @@ -67,10 +83,16 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Improve the compatibility between ongoing log backup and snapshot restore [#58685](https://github.com/pingcap/tidb/issues/58685) @[BornChanger](https://github.com/BornChanger) - Starting from v9.0.0, when a log backup task is running, if the conditions are met, you can still perform snapshot restore and allow the restored data to be properly recorded by the ongoing log backup. This enables ongoing log backups to proceed without having to stop them during the restore procedure. + Starting from v8.5.5, log backups can continue to run when performing a snapshot restore (when prerequisite conditions are met). This enables ongoing log backups to proceed without having to stop them during the restore procedure. The newly restored data will also be recorded in the ongoing log backup. For more information, see [documentation](/br/br-pitr-manual.md#compatibility-between-ongoing-log-backup-and-snapshot-restore). +* Table level restores from Log Backups [#57613](https://github.com/pingcap/tidb/issues/57613) @[Tristan1900](https://github.com/Tristan1900) + + Starting from v8.5.5, individual table level point in time recoveries can now be performed from log backups using filters. Being able to restore individual tables, instead of the full cluster, to a specific point in time enables much more flexible, and less impactful, recovery options. + + For more information, see [documentation](/br/br-pitr-manual.md#restore-data-using-filters). + * Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. From b19b87e4f5acc971712b6a9543a65013ca8b1a45 Mon Sep 17 00:00:00 2001 From: Ben Meadowcroft Date: Wed, 17 Dec 2025 18:15:39 -0800 Subject: [PATCH 04/45] Apply suggestions from code review Co-authored-by: Grace Cai --- releases/release-8.5.5.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index ce5a8955a7e44..dbc4ea5e867b2 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -63,7 +63,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- To protect the PD leader from overloading due to retry storms or similar feedback loops, a circuit breaker pattern is introduced to limit incoming traffic (when a threshold of errors is reached) to enable the system to stabilize. The `tidb_cb_pd_metadata_error_rate_threshold_ratio` system variable is used to control the application of the circuit breaker. - For more information, see [Documentation](/system-variables.md#tidb_cb_pd_metadata_error_rate_threshold_ratio-new-in-v900). + For more information, see [Documentation](https://docs.pingcap.com/tidb/v8.5/system-variables#tidb_cb_pd_metadata_error_rate_threshold_ratio-new-in-v855). * Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** @@ -85,7 +85,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- Starting from v8.5.5, log backups can continue to run when performing a snapshot restore (when prerequisite conditions are met). This enables ongoing log backups to proceed without having to stop them during the restore procedure. The newly restored data will also be recorded in the ongoing log backup. - For more information, see [documentation](/br/br-pitr-manual.md#compatibility-between-ongoing-log-backup-and-snapshot-restore). + For more information, see [documentation](https://docs.pingcap.com/tidb/v8.5/br-pitr-manual#compatibility-between-ongoing-log-backup-and-snapshot-restore). * Table level restores from Log Backups [#57613](https://github.com/pingcap/tidb/issues/57613) @[Tristan1900](https://github.com/Tristan1900) From af5952eddb3c4d40286b4fe41a8f46b043f67d35 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Thu, 18 Dec 2025 11:45:26 +0800 Subject: [PATCH 05/45] add two info --- releases/release-8.5.5.md | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index dbc4ea5e867b2..90bce6a56ff5e 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -23,7 +23,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Performance -* Point-in-time recovery (PITR) supports recovery from compacted log backups for faster restores [#56522](https://github.com/pingcap/tidb/issues/56522) @[YuJuncen](https://github.com/YuJuncen) +* Point-in-time recovery (PITR) supports recovery from compacted log backups for faster restores [#56522](https://github.com/pingcap/tidb/issues/56522) @[YuJuncen](https://github.com/YuJuncen) **tw@lilin90** Starting from v8.5.5, the log backup compaction feature provides offline compaction capabilities, converting unstructured log backup data into structured SST files. This results in the following improvements: @@ -33,7 +33,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- For more information, see [documentation](/br/br-compact-log-backup.md). -* Accelerated recovery of system tables from backups [#58757](https://github.com/pingcap/tidb/issues/58757) @[Leavrth](https://github.com/Leavrth) **tw@xxx** +* Accelerated recovery of system tables from backups [#58757](https://github.com/pingcap/tidb/issues/58757) @[Leavrth](https://github.com/Leavrth) **tw@lilin90** When restoring system tables from a backup, BR now introduces a new `--fast-load-sys-tables` parameter to use physical restoration instead of logical restoration. This option completely overwrites/replaces the existing tables, instead of restoring into them, for faster restoration for large scale deployments. @@ -47,7 +47,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Reliability -* Improved store scheduling in presence of network jitter [#9359](https://github.com/tikv/pd/issues/9359) @[okJiang](https://github.com/okJiang) **tw@xxx** +* Improved store scheduling in presence of network jitter [#9359](https://github.com/tikv/pd/issues/9359) @[okJiang](https://github.com/okJiang) **tw@qiancai** Provides a network status feedback mechanism to PD to avoid scheduling the leaders back to a problematic node (experiencing network jitter) after the leaders had been transferred off the node by TiKVs detection of the network jitter. @@ -59,7 +59,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Availability -* Introduce Client Circuit Breaker Pettern for PD [#8678](https://github.com/tikv/pd/issues/8678) @[Tema](https://github.com/Tema) **tw@xxx** +* Introduce Client Circuit Breaker Pettern for PD [#8678](https://github.com/tikv/pd/issues/8678) @[Tema](https://github.com/Tema) **tw@hfxsd** To protect the PD leader from overloading due to retry storms or similar feedback loops, a circuit breaker pattern is introduced to limit incoming traffic (when a threshold of errors is reached) to enable the system to stabilize. The `tidb_cb_pd_metadata_error_rate_threshold_ratio` system variable is used to control the application of the circuit breaker. @@ -81,13 +81,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### DB operations -* Improve the compatibility between ongoing log backup and snapshot restore [#58685](https://github.com/pingcap/tidb/issues/58685) @[BornChanger](https://github.com/BornChanger) +* Improve the compatibility between ongoing log backup and snapshot restore [#58685](https://github.com/pingcap/tidb/issues/58685) @[BornChanger](https://github.com/BornChanger) **tw@lilin90** Starting from v8.5.5, log backups can continue to run when performing a snapshot restore (when prerequisite conditions are met). This enables ongoing log backups to proceed without having to stop them during the restore procedure. The newly restored data will also be recorded in the ongoing log backup. For more information, see [documentation](https://docs.pingcap.com/tidb/v8.5/br-pitr-manual#compatibility-between-ongoing-log-backup-and-snapshot-restore). -* Table level restores from Log Backups [#57613](https://github.com/pingcap/tidb/issues/57613) @[Tristan1900](https://github.com/Tristan1900) +* Table level restores from Log Backups [#57613](https://github.com/pingcap/tidb/issues/57613) @[Tristan1900](https://github.com/Tristan1900) **tw@lilin90** Starting from v8.5.5, individual table level point in time recoveries can now be performed from log backups using filters. Being able to restore individual tables, instead of the full cluster, to a specific point in time enables much more flexible, and less impactful, recovery options. From f78c3bafcf8d51b0b9a312b17dcd9d9065d0e59b Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Wed, 24 Dec 2025 11:48:11 +0800 Subject: [PATCH 06/45] Update releases/release-8.5.5.md Co-authored-by: okJiang --- releases/release-8.5.5.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 90bce6a56ff5e..1e365fb0beab7 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -49,7 +49,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Improved store scheduling in presence of network jitter [#9359](https://github.com/tikv/pd/issues/9359) @[okJiang](https://github.com/okJiang) **tw@qiancai** - Provides a network status feedback mechanism to PD to avoid scheduling the leaders back to a problematic node (experiencing network jitter) after the leaders had been transferred off the node by TiKVs detection of the network jitter. + Provides a network status feedback mechanism to PD to avoid re-scheduling the leaders back to a problematic node (experiencing network jitter) after the leaders had been transferred off the node by TiKV raft mechanism. If the network continues to jitter, PD will actively evict leader from jittering node. * Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** From c7d930038486bcd7635eeb1cd7071baabd9923d9 Mon Sep 17 00:00:00 2001 From: qiancai Date: Wed, 24 Dec 2025 16:32:48 +0800 Subject: [PATCH 07/45] add improvements and bug fixes --- releases/release-8.5.5.md | 113 +++++++++++++++++++++++++++++++++++++- 1 file changed, 112 insertions(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 1e365fb0beab7..a360b28a4f6f6 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -151,4 +151,115 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ## Improvements -## Bug fixes \ No newline at end of file ++ TiDB + + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - (dup): release-9.0.0.md > Improvements> TiDB - Optimize the CPU usage of internal SQL statements in the Distributed eXecution Framework (DXF) [#59344](https://github.com/pingcap/tidb/issues/59344) @[D3Hunter](https://github.com/D3Hunter) + ++ TiKV + + - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - (dup): release-9.0.0.md > Improvements> TiKV - Throttle BR log restore requests when TiKV memory usage is high to prevent TiKV OOM [#18124](https://github.com/tikv/tikv/issues/18124) @[3pointer](https://github.com/3pointer) + ++ PD + + - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + ++ TiFlash + + - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + ++ Tools + + + Backup & Restore (BR) + + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + + + TiCDC + + - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + + + TiDB Data Migration (DM) + + - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + + + TiDB Lightning + + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + + + Dumpling + + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + + + TiUP + + - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + +## Bug fixes + ++ TiDB + + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - (dup): release-9.0.0.md > Bug fixes> TiDB - Fix the potential OOM issue when querying `information_schema.tables` by improving memory usage monitoring when quering system tables [#58985](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) + ++ TiKV + + - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + ++ PD + + - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + ++ TiFlash + + - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + ++ Tools + + + Backup & Restore (BR) + + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + + + TiCDC + + - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + + + TiDB Data Migration (DM) + + - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + + + TiDB Lightning + + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + + + Dumpling + + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + + + TiUP + + - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + +## Other dup notes + +- (dup): release-9.0.0.md > # Observability * Add storage engine identifiers to statement summary tables and slow query logs [#61736](https://github.com/pingcap/tidb/issues/61736) @[henrybw](https://github.com/henrybw) **tw@Oreoxmt** From 609017fc7a0ee2740931be0f912c5ffeee3b3880 Mon Sep 17 00:00:00 2001 From: qiancai Date: Thu, 25 Dec 2025 10:22:23 +0800 Subject: [PATCH 08/45] add more features and adjust the feature order --- releases/release-8.5.5.md | 92 ++++++++++++++++++++++----------------- 1 file changed, 52 insertions(+), 40 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index a360b28a4f6f6..65b352c58baf0 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -13,17 +13,49 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ## Features -### Scalability +### Performance -* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** +* 大幅提升特定有损 DDL 操作的执行效率，例如 `BIGINT → INT`、`CHAR(120) → VARCHAR(60)`。在未发生数据截断的前提下，执行耗时可从数小时缩短至分钟级、秒级甚至毫秒级，性能提升可达到数十倍至数十万倍。 [#63366](https://github.com/pingcap/tidb/issues/63366) [@wjhuang2016](https://github.com/wjhuang2016), [@tangenta](https://github.com/tangenta), [@fzzf678](https://github.com/fzzf678)**tw@qiancai** - Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + 优化策略包括： - For more information, see [Documentation](link). + - 在严格 SQL 模式下，预先检查类型转换过程中是否存在数据截断风险； + - 若不存在数据截断风险，则仅更新元数据，尽量避免索引重建； + - 如需重建索引，则采用更高效的 Ingest 流程，大幅提升索引重建性能。 -### Performance + 性能提升示例（基于 100 GiB 表的基准测试）： + + | 场景 | 操作类型 | 优化前 | 优化后 | 性能提升 | + |------|----------|--------|--------|----------| + | 无索引列 | `BIGINT → INT` | 2 小时 34 分 | 1 分 5 秒 | 142× | + | 有索引列 | `BIGINT → INT` | 6 小时 25 分 | 0.05 秒 | 460,000× | + | 有索引列 | `CHAR(120) → VARCHAR(60)` | 7 小时 16 分 | 12 分 56 秒 | 34× | + + 注：以上数据基于 DDL 执行过程中未发生数据截断的前提。以上优化对于有 TiFlash 副本的表，以及 sign <--> unsign 数据类型修改的场景不会生效。 + + 更多信息，请参考[用户文档](链接)。 + +* 优化了存在大量外键场景下的 DDL 性能，逻辑 DDL 性能最高可提升 25 倍 [#61126](https://github.com/pingcap/tidb/issues/61126) @[GMHDBJD](https://github.com/GMHDBJD) **tw@hfxsd** + + 在 v8.5.5 版本之前，当一些用户单个集群的表数量达到 1000 万级别，且其中有几十万张表有外键的场景，创建表，给表加列这些逻辑 DDL 的性能 QPS 会降低到 4，使得一些多租户的 SaaS 场景下的运维操作变得非常低效。在 v8.5.5 对该场景做了优化。经测试，1000 万张表，其中 20 万张表有外键的场景下，创建表，加列这类逻辑 DDL 的性能 QPS 稳定保持在 100，性能有 25 倍的提升。 + + 更多信息，请参考[用户文档](链接)。 + +* 提示索引下推到TiKV提升查询性能 [#62575](https://github.com/pingcap/tidb/issues/62575) @[lcwangchao](https://github.com/lcwangchao) **tw@qiancai** + + 通过hint INDEX_LOOKUP_PUSHDOWN(t1_name, idx1_name [, idx2_name ...]) 提示优化器将指定索引查询下推到TiKV，减少远程调用的次数，经过测试数据对比显示性能可提升约20%左右，最优可提升到40%。本特性一般建议结合表 affinity 属性使用，即表属性 AFFINITY="table" 或者 分区表属性 AFFINITY="partition" 。 + + 通过hint NO_INDEX_LOOKUP_PUSHDOWN(t1_name) 明确提示优化器不要将对应表的索引查询下推到TiKV执行。 -* Point-in-time recovery (PITR) supports recovery from compacted log backups for faster restores [#56522](https://github.com/pingcap/tidb/issues/56522) @[YuJuncen](https://github.com/YuJuncen) **tw@lilin90** + 更多信息，请参考[optimizer-hints.md](https://docs.pingcap.com/zh/tidb/stable/optimizer-hints/)。 + +* 表级和分区级亲和性属性 AFFINITY [#9764](https://github.com/tikv/pd/issues/9764) @[lhy1024](https://github.com/lhy1024) **tw@qiancai** + + 为表或者分区表新增亲和性属性，设置亲和性属性后，PD会将表或分区的Region归为相同的一个亲和性分组中，这些Region的Leader、Voter 会被优先调度到指定TiKV Store上。有AFFNITY属性的表和分区在查询时，由于索引、表数据的Region都在一个TiKV Store上，因此优化器可结合 hint INDEX_LOOKUP_PUSHDOWN 指定将对应索引查询下推，减少跨节点分散查询带来的延迟，根据测试数据对比性能可约提升20%。 + + 更多信息，请参考[table-affinity.md](table-affinity.md)。 + +* Point-in-time recovery (PITR) supports recovery from compacted log backups for faster restores [#56522](https://github.com/pingcap/tidb/issues/56522) @[YuJuncen](https://github.com/YuJuncen) **tw@lilin90** Starting from v8.5.5, the log backup compaction feature provides offline compaction capabilities, converting unstructured log backup data into structured SST files. This results in the following improvements: @@ -39,24 +71,12 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- For more information, see [Documentation](/br/br-snapshot-guide.md#restore-tables-in-the-mysql-schema). -* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** - - Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. - - For more information, see [Documentation](link). - ### Reliability * Improved store scheduling in presence of network jitter [#9359](https://github.com/tikv/pd/issues/9359) @[okJiang](https://github.com/okJiang) **tw@qiancai** Provides a network status feedback mechanism to PD to avoid re-scheduling the leaders back to a problematic node (experiencing network jitter) after the leaders had been transferred off the node by TiKV raft mechanism. If the network continues to jitter, PD will actively evict leader from jittering node. -* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** - - Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. - - For more information, see [Documentation](link). - ### Availability * Introduce Client Circuit Breaker Pettern for PD [#8678](https://github.com/tikv/pd/issues/8678) @[Tema](https://github.com/Tema) **tw@hfxsd** @@ -65,21 +85,21 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- For more information, see [Documentation](https://docs.pingcap.com/tidb/v8.5/system-variables#tidb_cb_pd_metadata_error_rate_threshold_ratio-new-in-v855). -* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** +### SQL - Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. +* 支持在线修改分布式 ADD Index 任务的并发和吞吐 [#62120](https://github.com/pingcap/tidb/pull/62120) @[joechenrh](https://github.com/joechenrh) **tw@qiancai** - For more information, see [Documentation](link). + 在 v8.5.5 版本之前，当集群开启了分布式执行框架 [tidb_enable_dist_task](/system-variables/#tidb_enable_dist_task-从-v710-版本开始引入) ，在 ADD Index 任务执行期间，是无法修改该任务的 `THREAD`， `BATCH_SIZE`，`MAX_WRITE_SPEED` 参数。需要取消该 DDL 任务，重新设置参数后再提交，效率较低。支持该功能后，用户可以根据业务负载和对 ADD Index 的性能要求，在线灵活调整这些参数。 -### SQL + 更多信息，请参考[ADMIN ALTER DDL JOBS](/sql-statement-admin-alter-ddl/#admin-alter-ddl-jobs)。 -* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** +### DB operations - Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. +* TiKV 支持优雅关闭 (graceful shutdown) [#17221](https://github.com/tikv/tikv/issues/17221) @[hujiatao0](https://github.com/hujiatao0) **tw@qiancai** - For more information, see [Documentation](link). + 在关闭 TiKV 服务器时，TiKV 会尽量将其上的 leader 副本转移到其他 TiKV 节点，然后再关闭。该等待期默认为 20 秒，可通过 [`server.graceful-shutdown-timeout`](https://docs.pingcap.com/zh/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-从-v855-版本开始引入) 配置项进行调整。若达到该超时时间后仍有 leader 未完成转移，TiKV 将跳过剩余 leader 的转移，直接进入关闭流程。 -### DB operations + 更多信息，请参考[用户文档](https://docs.pingcap.com/zh/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-从-v855-版本开始引入)。 * Improve the compatibility between ongoing log backup and snapshot restore [#58685](https://github.com/pingcap/tidb/issues/58685) @[BornChanger](https://github.com/BornChanger) **tw@lilin90** @@ -93,12 +113,6 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- For more information, see [documentation](/br/br-pitr-manual.md#restore-data-using-filters). -* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** - - Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. - - For more information, see [Documentation](link). - ### Observability * Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** @@ -109,17 +123,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Security -* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** +* Enable Azure Managed Identity (MI) authentication for Backup & Restore (BR) to Azure Blob Storage. **tw@qiancai** - Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + Starting from v8.5.5, TiDB Backup & Restore supports Azure Managed Identity (MI) for authenticating to Azure Blob Storage, eliminating the need for static SAS tokens. This enables secure, keyless, and ephemeral authentication aligned with Azure best practices. - For more information, see [Documentation](link). - -### Data migration - -* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** + With this feature, BR and the embedded BR worker in TiKV can acquire access tokens directly from Azure Instance Metadata Service (IMDS), reducing credential leakage risk and simplifying credential rotation for self-managed and cloud deployments on Azure. - Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + This enhancement is particularly useful for enterprise customers running TiDB on Azure Kubernetes Service (AKS) or other Azure environments that require strict security controls for backup and restore workflows. For more information, see [Documentation](link). @@ -127,6 +137,8 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Behavior changes +* When using [`IMPORT INTO`](/sql-statements/sql-statement-import-into.md) with [Global Sort](/tidb-global-sort.md) enabled, primary key or unique index conflicts are now automatically resolved by removing all conflicting rows (none of the conflicting rows are preserved), instead of causing the task to fail. The number of conflicted rows appears in the `Result_Message` column of `SHOW IMPORT JOBS` output, and detailed conflict information is stored in cloud storage. For more information, see [`IMPORT INTO` conflict resolution](/sql-statements/sql-statement-import-into.md#conflict-resolution). + ### MySQL compatibility ### System variables From 408f0194c7824b6bcc6a03da1b6ef99fed946812 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Thu, 25 Dec 2025 11:07:43 +0800 Subject: [PATCH 09/45] Update releases/release-8.5.5.md --- releases/release-8.5.5.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 65b352c58baf0..cedc15dc1979d 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -41,7 +41,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- 更多信息，请参考[用户文档](链接)。 -* 提示索引下推到TiKV提升查询性能 [#62575](https://github.com/pingcap/tidb/issues/62575) @[lcwangchao](https://github.com/lcwangchao) **tw@qiancai** +* 提示索引下推到TiKV提升查询性能 [#62575](https://github.com/pingcap/tidb/issues/62575) @[lcwangchao](https://github.com/lcwangchao) **tw@Oreoxmt** 通过hint INDEX_LOOKUP_PUSHDOWN(t1_name, idx1_name [, idx2_name ...]) 提示优化器将指定索引查询下推到TiKV，减少远程调用的次数，经过测试数据对比显示性能可提升约20%左右，最优可提升到40%。本特性一般建议结合表 affinity 属性使用，即表属性 AFFINITY="table" 或者 分区表属性 AFFINITY="partition" 。 From 493e5bb20b4e8966ab585474afc4ca9eb5b58411 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Thu, 25 Dec 2025 11:08:47 +0800 Subject: [PATCH 10/45] Apply suggestions from code review --- releases/release-8.5.5.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index cedc15dc1979d..4c434128a457e 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -123,7 +123,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Security -* Enable Azure Managed Identity (MI) authentication for Backup & Restore (BR) to Azure Blob Storage. **tw@qiancai** +* Enable Azure Managed Identity (MI) authentication for Backup & Restore (BR) to Azure Blob Storage [#19006](https://github.com/tikv/tikv/issues/19006) @[RidRisR](https://github.com/RidRisR) **tw@qiancai** Starting from v8.5.5, TiDB Backup & Restore supports Azure Managed Identity (MI) for authenticating to Azure Blob Storage, eliminating the need for static SAS tokens. This enables secure, keyless, and ephemeral authentication aligned with Azure best practices. From ea2f6c4d1bc27c22f7609e39868201f24c02ac8f Mon Sep 17 00:00:00 2001 From: Aolin Date: Thu, 25 Dec 2025 15:25:51 +0800 Subject: [PATCH 11/45] update INDEX_LOOKUP_PUSHDOWN --- releases/release-8.5.5.md | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 4c434128a457e..682ee2ec8b2eb 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -41,13 +41,15 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- 更多信息，请参考[用户文档](链接)。 -* 提示索引下推到TiKV提升查询性能 [#62575](https://github.com/pingcap/tidb/issues/62575) @[lcwangchao](https://github.com/lcwangchao) **tw@Oreoxmt** +* Support pushing index lookups down to TiKV to improve query performance [#62575](https://github.com/pingcap/tidb/issues/62575) @[lcwangchao](https://github.com/lcwangchao) - 通过hint INDEX_LOOKUP_PUSHDOWN(t1_name, idx1_name [, idx2_name ...]) 提示优化器将指定索引查询下推到TiKV，减少远程调用的次数，经过测试数据对比显示性能可提升约20%左右，最优可提升到40%。本特性一般建议结合表 affinity 属性使用，即表属性 AFFINITY="table" 或者 分区表属性 AFFINITY="partition" 。 + Starting from v8.5.5, TiDB supports using optimizer hints to push the `IndexLookUp` operator down to TiKV nodes. This reduces the number of remote procedure calls (RPCs) and can improve query performance. The actual performance improvement varies depending on the specific workload and requires testing for verification. - 通过hint NO_INDEX_LOOKUP_PUSHDOWN(t1_name) 明确提示优化器不要将对应表的索引查询下推到TiKV执行。 + You can use the [`INDEX_LOOKUP_PUSHDOWN(t1_name, idx1_name [, idx2_name ...])`](https://docs.pingcap.com/tidb/stable/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855) hint to explicitly instruct the optimizer to push index lookups down to TiKV for a specific table. It is recommended to combine this hint with the table's AFFINITY attribute. For example, set `AFFINITY="table"` for regular tables and `AFFINITY="partition"` for partitioned tables. - 更多信息，请参考[optimizer-hints.md](https://docs.pingcap.com/zh/tidb/stable/optimizer-hints/)。 + To disable index lookup pushdown to TiKV for a specific table, use the [`NO_INDEX_LOOKUP_PUSHDOWN(t1_name)`](https://docs.pingcap.com/tidb/stable/optimizer-hints#no_index_lookup_pushdownt1_name--new-in-v855) hint. + + For more information, see [documentation](https://docs.pingcap.com/tidb/stable/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855). * 表级和分区级亲和性属性 AFFINITY [#9764](https://github.com/tikv/pd/issues/9764) @[lhy1024](https://github.com/lhy1024) **tw@qiancai** From c71d5e0209596491c91876a9feaf9e5596f4e333 Mon Sep 17 00:00:00 2001 From: xixirangrang Date: Fri, 26 Dec 2025 09:08:31 +0800 Subject: [PATCH 12/45] Apply suggestions from code review --- releases/release-8.5.5.md | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 682ee2ec8b2eb..f7977e328bc10 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -35,11 +35,11 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- 更多信息，请参考[用户文档](链接)。 -* 优化了存在大量外键场景下的 DDL 性能，逻辑 DDL 性能最高可提升 25 倍 [#61126](https://github.com/pingcap/tidb/issues/61126) @[GMHDBJD](https://github.com/GMHDBJD) **tw@hfxsd** +* Improve DDL performance in scenarios with a large number of foreign keys, with up to a 25x increase in logical DDL performance [#61126](https://github.com/pingcap/tidb/issues/61126) @[GMHDBJD](https://github.com/GMHDBJD) **tw@hfxsd** - 在 v8.5.5 版本之前，当一些用户单个集群的表数量达到 1000 万级别，且其中有几十万张表有外键的场景，创建表，给表加列这些逻辑 DDL 的性能 QPS 会降低到 4，使得一些多租户的 SaaS 场景下的运维操作变得非常低效。在 v8.5.5 对该场景做了优化。经测试，1000 万张表，其中 20 万张表有外键的场景下，创建表，加列这类逻辑 DDL 的性能 QPS 稳定保持在 100，性能有 25 倍的提升。 + Before v8.5.5, in scenarios involving ultra-large-scale tables (for example, a cluster with 10 million tables in total, including hundreds of thousands of tables with foreign keys), the performance of logical DDL operations (such as creating tables or adding columns) can drop to approximately 4 QPS. This leads to low operational efficiency in multi-tenant SaaS environments. - 更多信息，请参考[用户文档](链接)。 + TiDB v8.5.5 optimizes these scenarios. Test results show that in an extreme environment with 10 million tables (including 200,000 tables with foreign keys), the logical DDL processing performance consistently maintains 100 QPS. Compared to previous versions, the performance is improved by 25 times, significantly enhancing the operational responsiveness of ultra-large-scale clusters. * Support pushing index lookups down to TiKV to improve query performance [#62575](https://github.com/pingcap/tidb/issues/62575) @[lcwangchao](https://github.com/lcwangchao) @@ -81,11 +81,11 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Availability -* Introduce Client Circuit Breaker Pettern for PD [#8678](https://github.com/tikv/pd/issues/8678) @[Tema](https://github.com/Tema) **tw@hfxsd** +* Introduce the client circuit breaker pattern for PD [#8678](https://github.com/tikv/pd/issues/8678) @[Tema](https://github.com/Tema) **tw@hfxsd** - To protect the PD leader from overloading due to retry storms or similar feedback loops, a circuit breaker pattern is introduced to limit incoming traffic (when a threshold of errors is reached) to enable the system to stabilize. The `tidb_cb_pd_metadata_error_rate_threshold_ratio` system variable is used to control the application of the circuit breaker. + To protect the PD leader from overloading during retry storms or similar feedback loops, TiDB now implements a circuit breaker pattern. When the error rate reaches a predefined threshold, the circuit breaker limits incoming traffic to allow the system to recover and stabilize. You can use the `tidb_cb_pd_metadata_error_rate_threshold_ratio` system variable to control the circuit breaker. - For more information, see [Documentation](https://docs.pingcap.com/tidb/v8.5/system-variables#tidb_cb_pd_metadata_error_rate_threshold_ratio-new-in-v855). + For more information, see [Documentation](/system-variables.md#tidb_cb_pd_metadata_error_rate_threshold_ratio-new-in-v855). ### SQL From e8314fe28aea847e3193017fedffd9a001f8b18e Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Mon, 29 Dec 2025 15:02:45 +0800 Subject: [PATCH 13/45] add the feature description for storage engine identifiers --- releases/release-8.5.5.md | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index f7977e328bc10..fe9d408441098 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -117,11 +117,23 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Observability -* Placeholder for feature summary [#Issue-number](issue-link) @[Contributor-GitHub-ID](id-link) **tw@xxx** +* Add storage engine identifiers to statement summary tables and slow query logs [#61736](https://github.com/pingcap/tidb/issues/61736) @[henrybw](https://github.com/henrybw) **tw@Oreoxmt** - Provide a concise overview of what the feature is, the value it offers to users, and include a brief sentence on how to use it effectively. If there are any particularly important aspects of this feature, be sure to mention them as well. + When both TiKV and TiFlash are deployed in a cluster, users often need to filter SQL statements by storage engine during database diagnostics and performance optimization. For example, if TiFlash is under high load, users might need to identify SQL statements running on TiFlash to locate potential causes. To meet this need, starting from v9.0.0, TiDB adds storage engine identifier fields to statement summary tables and slow query logs. - For more information, see [Documentation](link). + New fields in [statement summary tables](/statement-summary-tables.md): + + * `STORAGE_KV`: `1` indicates that the SQL statement accesses TiKV. + * `STORAGE_MPP`: `1` indicates that the SQL statement accesses TiFlash. + + New fields in [slow query logs](/identify-slow-queries.md): + + * `Storage_from_kv`: `true` indicates that the SQL statement accesses TiKV. + * `Storage_from_mpp`: `true` indicates that the SQL statement accesses TiFlash. + + This feature simplifies workflows in certain diagnostics and performance optimization scenarios and improves issue identification efficiency. + + For more information, see [Statement Summary Tables](/statement-summary-tables.md) and [Identify Slow Queries](/identify-slow-queries.md). ### Security From 0d5f07cb1f3974db0c032760911b398fef08935c Mon Sep 17 00:00:00 2001 From: xixirangrang Date: Mon, 29 Dec 2025 15:04:37 +0800 Subject: [PATCH 14/45] Update releases/release-8.5.5.md --- releases/release-8.5.5.md | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index fe9d408441098..44816886a3bd4 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -159,7 +159,8 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- | Variable name | Change type | Description | |--------|------------------------------|------| -| | | | +| `tidb_advancer_check_point_lag_limit` | Newly added | Controls the maximum allowed checkpoint lag for a log backup task. If a task's checkpoint lag exceeds this limit, TiDB Advancer pauses the task. | +| `tidb_cb_pd_metadata_error_rate_threshold_ratio` | Newly added | Controls when TiDB triggers the circuit breaker. Setting a value of `0` (default) disables the circuit breaker. Setting a value between `0.01` and `1` enables it, causing the circuit breaker to trigger when the error rate of specific requests sent to PD reaches or exceeds the threshold. | | | | | | | | | From c39dd487a5cec98eaf2c37ed47502158bff04e5d Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Tue, 30 Dec 2025 11:26:31 +0800 Subject: [PATCH 15/45] add cdc bug fixes Co-authored-by: hongyunyan <649330952@qq.com> --- releases/release-8.5.5.md | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 44816886a3bd4..10a65422b90de 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -264,7 +264,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiCDC - - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - Fix the issue that may cause DML loss while failing to close the writer of the storage sink [#12436](https://github.com/pingcap/tiflow/issues/12436) @[wk989898](https://github.com/wk989898) + - Fix the issue that causes the changefeed to fail when truncating partition tables [#12430](https://github.com/pingcap/tiflow/issues/12430) @[wk989898](https://github.com/wk989898) + - Fix the incorrect execution order of split DDLs generated from a multi-table DDL statement [#12449](https://github.com/pingcap/tiflow/issues/12449) @[wlwilliamx](https://github.com/wlwilliamx) + - Add more verification for the changefeed config when creating changefeed. [#12253](https://github.com/pingcap/tiflow/issues/12253) @[wk989898](https://github.com/wk989898) + - Upgrade aws-sdk-go-v2 dependency to fix glue schema registry[#12424](https://github.com/pingcap/tiflow/issues/12424) @[wk989898](https://github.com/wk989898) + - Fix the issue that may cause the sink memory quota not to be released [#18169](https://github.com/tikv/tikv/issues/18169) @[asddongmen](https://github.com/asddongmen) + - Fix the issue that may cause the sink memory quota not to be released [#18915](https://github.com/tikv/tikv/issues/18915) @[asddongmen](https://github.com/asddongmen) - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + TiDB Data Migration (DM) From ca80447d1a398f636ba413272e70d0f1a8bd6429 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Tue, 30 Dec 2025 11:31:22 +0800 Subject: [PATCH 16/45] add improvements and bug fixes for SQL data Co-authored-by: Ruihao Chen --- releases/release-8.5.5.md | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 10a65422b90de..00a9463d1c0f6 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -181,7 +181,8 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiDB - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) +- improve the error message for import into when there are encoding errors [#issue](https://github.com/pingcap/tidb/issues/63763) @[D3Hunter](https://github.com/D3Hunter) +- change the parser for parquet format to get better performance [#issue](https://github.com/pingcap/tidb/issues/62906) @[joechenrh](https://github.com/joechenrh) - (dup): release-9.0.0.md > Improvements> TiDB - Optimize the CPU usage of internal SQL statements in the Distributed eXecution Framework (DXF) [#59344](https://github.com/pingcap/tidb/issues/59344) @[D3Hunter](https://github.com/D3Hunter) + TiKV @@ -236,7 +237,22 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiDB - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) +- fix the problem that foreign key is not updated after modify column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) +- fix error decoding `RENAME TABLE` job arg from older version TiDB [#issue](https://github.com/pingcap/tidb/issues/64413) @[joechenrh](https://github.com/joechenrh) +- fix missing rebase auto increment not executed if BR restore failed [#issue](https://github.com/pingcap/tidb/issues/64761) @[joechenrh](https://github.com/joechenrh) +- fix OOM issue when querying `information_schema` tables [#issue](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) +- fix the problem that TiDB node may stuck during upgrade [#issue](https://github.com/pingcap/tidb/issues/64539) @[joechenrh](https://github.com/joechenrh) +- fix unexpected successful admin check when there are no index record [#issue](https://github.com/pingcap/tidb/issues/63698) @[wjhuang2016](https://github.com/wjhuang2016) +- fix data-index inconsistency when chaning collation with modify column [#issue](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) +- fix incorrect initialization for foreign key related fields when copying table info [#issue](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) +- fix the problem that embedded analyze may be not triggered for multi schema change [#issue](https://github.com/pingcap/tidb/issues/65040) @[joechenrh](https://github.com/joechenrh) +- fix the problem that the DXF task was not cancelled after canceling the add index job [#issue](https://github.com/pingcap/tidb/issues/64129) @[tangenta](https://github.com/tangenta) +- fix incorrect check to determing whether to load table info for tables contain foreign key [#issue](https://github.com/pingcap/tidb/issues/60444) @[JQWong7](https://github.com/JQWong7) +- fix incorrect auto ID setting after cross-database rename table [#issue](https://github.com/pingcap/tidb/issues/64561) @[joechenrh](https://github.com/joechenrh) +- fix incorrect handling meta key for older version of TiDB [#issue](https://github.com/pingcap/tidb/issues/64323) @[wjhuang2016](https://github.com/wjhuang2016) +- fix ligtning doesnt' report error for schema files without trailing semicolon [#issue](https://github.com/pingcap/tidb/issues/63414) @[GMHDBJD](https://github.com/GMHDBJD) +- fix the dead loop when reading files during IMPORT INTO global sort [#issue](https://github.com/pingcap/tidb/issues/61177) @[CbcWestwolf](https://github.com/CbcWestwolf) +- fix the panic when processing generated columns for IMPORT INTO [#issue](https://github.com/pingcap/tidb/issues/64657) @[D3Hunter](https://github.com/D3Hunter) - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - (dup): release-9.0.0.md > Bug fixes> TiDB - Fix the potential OOM issue when querying `information_schema.tables` by improving memory usage monitoring when quering system tables [#58985](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) From 82305679708a43588509f6b78ee55c88cb0a879b Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Tue, 30 Dec 2025 11:55:31 +0800 Subject: [PATCH 17/45] move ticdc #12253 from bug fixes to improvements --- releases/release-8.5.5.md | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 00a9463d1c0f6..1a42e4f99a983 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -210,8 +210,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiCDC - - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - Add more verification for the changefeed config when creating changefeed. [#12253](https://github.com/pingcap/tiflow/issues/12253) @[wk989898](https://github.com/wk989898) + TiDB Data Migration (DM) @@ -283,7 +282,6 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - Fix the issue that may cause DML loss while failing to close the writer of the storage sink [#12436](https://github.com/pingcap/tiflow/issues/12436) @[wk989898](https://github.com/wk989898) - Fix the issue that causes the changefeed to fail when truncating partition tables [#12430](https://github.com/pingcap/tiflow/issues/12430) @[wk989898](https://github.com/wk989898) - Fix the incorrect execution order of split DDLs generated from a multi-table DDL statement [#12449](https://github.com/pingcap/tiflow/issues/12449) @[wlwilliamx](https://github.com/wlwilliamx) - - Add more verification for the changefeed config when creating changefeed. [#12253](https://github.com/pingcap/tiflow/issues/12253) @[wk989898](https://github.com/wk989898) - Upgrade aws-sdk-go-v2 dependency to fix glue schema registry[#12424](https://github.com/pingcap/tiflow/issues/12424) @[wk989898](https://github.com/wk989898) - Fix the issue that may cause the sink memory quota not to be released [#18169](https://github.com/tikv/tikv/issues/18169) @[asddongmen](https://github.com/asddongmen) - Fix the issue that may cause the sink memory quota not to be released [#18915](https://github.com/tikv/tikv/issues/18915) @[asddongmen](https://github.com/asddongmen) From 5fd1c4466ccbe98ae699482a316ada6b7eb52d13 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Tue, 30 Dec 2025 11:56:07 +0800 Subject: [PATCH 18/45] add BR bug fixes MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Co-authored-by: 山岚 <36239017+YuJuncen@users.noreply.github.com> --- releases/release-8.5.5.md | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 1a42e4f99a983..a1d179657d617 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -275,7 +275,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + Backup & Restore (BR) - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - Fixed an issue that memory usage may be unacceptable when log backup enabled and many regions in cluster. [#18719](https://github.com/tikv/tikv/issues/18719) @[YuJuncen](https://github.com/YuJuncen) + - Fixed an issue that Azure SDK cannot found suitable key from environment. [#18206](https://github.com/tikv/tikv/issues/18206) @[YuJuncen](https://github.com/YuJuncen) + - Fixed an issue that foreign keys cannot be properly fixed during `restore point`. [#61642](https://github.com/pingcap/tidb/issues/61642) @[Leavrth](https://github.com/Leavrth) + - Fixed an issue that restore cannot be performed if system table collations are incompatible between backup and target cluster by introducing the parameter --sys-check-collation to support restore privileges tables from v6.5 to v7.5 [#64667](https://github.com/pingcap/tidb/issues/64667) @[Leavrth](https://github.com/Leavrth) + - Fixed an issue that caused `restore log` cannot be performed after a failed `restore point` though the latter is safe to be execued. [#64908](https://github.com/pingcap/tidb/issues/64908) @[RidRisR](https://github.com/RidRisR) + - Fixed an issue that Azure managed identity is unavailable.[#19006](https://github.com/tikv/tikv/issues/19006) @[RidRisR](https://github.com/RidRisR) + - Fixed an issue that may cause `restore point` from checkpoint panic when the log backup was mixed with a full backup. [#58685](https://github.com/pingcap/tidb/issues/58685) @[YuJuncen](https://github.com/YuJuncen) + TiCDC From 56ddb220e502ee66aeeae031af64355326fcbd48 Mon Sep 17 00:00:00 2001 From: Aolin Date: Wed, 31 Dec 2025 11:29:38 +0800 Subject: [PATCH 19/45] Compatibility changes: add tidb_index_lookup_pushdown_policy --- releases/release-8.5.5.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index a1d179657d617..268c9f270cd9f 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -161,7 +161,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- |--------|------------------------------|------| | `tidb_advancer_check_point_lag_limit` | Newly added | Controls the maximum allowed checkpoint lag for a log backup task. If a task's checkpoint lag exceeds this limit, TiDB Advancer pauses the task. | | `tidb_cb_pd_metadata_error_rate_threshold_ratio` | Newly added | Controls when TiDB triggers the circuit breaker. Setting a value of `0` (default) disables the circuit breaker. Setting a value between `0.01` and `1` enables it, causing the circuit breaker to trigger when the error rate of specific requests sent to PD reaches or exceeds the threshold. | -| | | | +| `tidb_index_lookup_pushdown_policy` | Newly added | Controls whether and when TiDB pushes the `IndexLookUp` operator down to TiKV. | | | | | ### Configuration parameters From 2b6605737d19542e1636c227e6bece07366e15d2 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Wed, 31 Dec 2025 13:27:13 +0800 Subject: [PATCH 20/45] add improvements and bug fixes for coprocessor/TiKV /engine/raft Co-authored-by: Bisheng Huang --- releases/release-8.5.5.md | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 268c9f270cd9f..c1128cac47050 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -187,8 +187,9 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiKV - - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - Introduces CPU-aware scaling for the unified read pool to avoid CPU starvation under hot read workloads. [#18464](https://github.com/tikv/tikv/issues/18464) @[mittalrishabh](https://github.com/mittalrishabh) + - Adds network latency awareness to slow score to avoid scheduling leaders on TiKV nodes with unstable network conditions. [#18797](https://github.com/tikv/tikv/issues/18797) @[okJiang](https://github.com/okJiang) + - Optimizes hibernate behavior by allowing leaders to enter hibernation once a majority vote is reached, without waiting for down non-voter peers. [#19070](https://github.com/tikv/tikv/issues/19070) @[jiadebin](https://github.com/jiadebin) - (dup): release-9.0.0.md > Improvements> TiKV - Throttle BR log restore requests when TiKV memory usage is high to prevent TiKV OOM [#18124](https://github.com/tikv/tikv/issues/18124) @[3pointer](https://github.com/3pointer) + PD @@ -257,8 +258,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiKV - - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/tikv/tikv/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - Fix the bug that analyze scan kv operation metric is always 0 [#19206](https://github.com/tikv/tikv/issues/19206) @[glorv](https://github.com/glorv) + - Fix the bug that pd heartbeat may report wrong region size/keys statistics data after leader change. [#19180](https://github.com/tikv/tikv/issues/19180) @[glorv](https://github.com/glorv) + - Fixes unsafe recovery getting stuck by removing tombstoned TiFlash learners from the unsafe recovery demotion list. [#18458](https://github.com/tikv/tikv/issues/18458) @[v01dstar](https://github.com/v01dstar) + - Fixes an issue where snapshots could be canceled indefinitely under continuous writes, blocking replica recovery. [#18872](https://github.com/tikv/tikv/issues/18872) @[exit-code-1](https://github.com/exit-code-1) + - Fixes compaction slowdowns caused by increased flow-control thresholds. [#18708](https://github.com/tikv/tikv/issues/18708) @[hhwyt](https://github.com/hhwyt) + - Fix the bug that pd heartbeat may report wrong region size/keys statistics data after leader change. [#19180](https://github.com/tikv/tikv/issues/19180) @[glorv](https://github.com/glorv) + - Fixes a corner case where Raft peers could enter hibernation prematurely, causing them to remain busy and block leader transfers after TiKV restart. [#19203](https://github.com/tikv/tikv/issues/19203) @[LykxSassinator](https://github.com/LykxSassinator) + PD From 7a82c46fddf7b855c7a764a3df1b63b6bd041fad Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Mon, 5 Jan 2026 09:38:27 +0800 Subject: [PATCH 21/45] Apply suggestions from code review --- releases/release-8.5.5.md | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index c1128cac47050..67041f2551a90 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -31,7 +31,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- | 有索引列 | `BIGINT → INT` | 6 小时 25 分 | 0.05 秒 | 460,000× | | 有索引列 | `CHAR(120) → VARCHAR(60)` | 7 小时 16 分 | 12 分 56 秒 | 34× | - 注：以上数据基于 DDL 执行过程中未发生数据截断的前提。以上优化对于有 TiFlash 副本的表，以及 sign <--> unsign 数据类型修改的场景不会生效。 + 注：以上数据基于 DDL 执行过程中未发生数据截断的前提。以上优化对于有 TiFlash 副本的表，以及符号类型转换场景（如 `Signed` ↔ `Unsigned`）场景不会生效。 更多信息，请参考[用户文档](链接)。 @@ -75,9 +75,11 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Reliability -* Improved store scheduling in presence of network jitter [#9359](https://github.com/tikv/pd/issues/9359) @[okJiang](https://github.com/okJiang) **tw@qiancai** +* Improve scheduling stability in TiKV during network jitter [#9359](https://github.com/tikv/pd/issues/9359) @[okJiang](https://github.com/okJiang) **tw@qiancai** - Provides a network status feedback mechanism to PD to avoid re-scheduling the leaders back to a problematic node (experiencing network jitter) after the leaders had been transferred off the node by TiKV raft mechanism. If the network continues to jitter, PD will actively evict leader from jittering node. + Starting from v8.5.5, TiKV introduces a network slow-node detection and feedback mechanism. When this mechanism is enabled, TiKV probes network latency between nodes, calculates a network slow score, and reports the score to PD. Based on this score, PD evaluates the network status of TiKV nodes and adjusts scheduling accordingly: when a TiKV node is detected to be experiencing network jitter, PD restricts the scheduling of new Leaders to that node; if the network jitter persists, PD proactively evicts existing Leaders from the affected node to other TiKV nodes, thereby reducing the impact of network issues on the cluster. + + For more information, see [documentation](/pd-control.md#scheduler-config-evict-slow-store-scheduler). ### Availability @@ -139,11 +141,11 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Enable Azure Managed Identity (MI) authentication for Backup & Restore (BR) to Azure Blob Storage [#19006](https://github.com/tikv/tikv/issues/19006) @[RidRisR](https://github.com/RidRisR) **tw@qiancai** - Starting from v8.5.5, TiDB Backup & Restore supports Azure Managed Identity (MI) for authenticating to Azure Blob Storage, eliminating the need for static SAS tokens. This enables secure, keyless, and ephemeral authentication aligned with Azure best practices. + Starting from v8.5.5, BR supports Azure Managed Identity (MI) for authenticating to Azure Blob Storage, eliminating the need for static SAS tokens. This enables secure, keyless, and ephemeral authentication that follows Azure best practices. With this feature, BR and the embedded BR worker in TiKV can acquire access tokens directly from Azure Instance Metadata Service (IMDS), reducing credential leakage risk and simplifying credential rotation for self-managed and cloud deployments on Azure. - This enhancement is particularly useful for enterprise customers running TiDB on Azure Kubernetes Service (AKS) or other Azure environments that require strict security controls for backup and restore workflows. + This enhancement is particularly useful for enterprise customers running TiDB on Azure Kubernetes Service (AKS) or other Azure environments that require strict security controls for backup and restore operations. For more information, see [Documentation](link). From cc39d05b320999b02c3d4719f703306f72bbc639 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Mon, 5 Jan 2026 11:07:12 +0800 Subject: [PATCH 22/45] translate #63366 --- releases/release-8.5.5.md | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 67041f2551a90..0a0a331960905 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -15,25 +15,25 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Performance -* 大幅提升特定有损 DDL 操作的执行效率，例如 `BIGINT → INT`、`CHAR(120) → VARCHAR(60)`。在未发生数据截断的前提下，执行耗时可从数小时缩短至分钟级、秒级甚至毫秒级，性能提升可达到数十倍至数十万倍。 [#63366](https://github.com/pingcap/tidb/issues/63366) [@wjhuang2016](https://github.com/wjhuang2016), [@tangenta](https://github.com/tangenta), [@fzzf678](https://github.com/fzzf678)**tw@qiancai** +* Introduce significant performance improvements for certain lossy DDL operations (such as `BIGINT → INT` and `CHAR(120) → VARCHAR(60)`): when no data truncation occurs, the execution time of these operations can be reduced from hours to minutes, seconds, or even milliseconds, delivering performance gains ranging from tens to hundreds of thousands of times [#63366](https://github.com/pingcap/tidb/issues/63366) [@wjhuang2016](https://github.com/wjhuang2016), [@tangenta](https://github.com/tangenta), [@fzzf678](https://github.com/fzzf678) **tw@qiancai** - 优化策略包括： + The optimization strategies are as follows: - - 在严格 SQL 模式下，预先检查类型转换过程中是否存在数据截断风险； - - 若不存在数据截断风险，则仅更新元数据，尽量避免索引重建； - - 如需重建索引，则采用更高效的 Ingest 流程，大幅提升索引重建性能。 + - In strict SQL mode, TiDB pre-checks for potential data truncation risks during type conversion. + - If no data truncation risk is detected, TiDB updates only the metadata and avoids index rebuilding whenever possible + - If index rebuilding is required, TiDB uses a more efficient ingest process to significantly improve index rebuild performance. - 性能提升示例（基于 100 GiB 表的基准测试）： + The following table shows example performance improvements based on benchmark tests on a table with 114 GiB of data and 600 million rows. The test cluster consists of 3 TiDB nodes, 6 TiKV nodes, and 1 PD node. All nodes are configured with 16 CPU cores and 32 GiB of memory. - | 场景 | 操作类型 | 优化前 | 优化后 | 性能提升 | - |------|----------|--------|--------|----------| - | 无索引列 | `BIGINT → INT` | 2 小时 34 分 | 1 分 5 秒 | 142× | - | 有索引列 | `BIGINT → INT` | 6 小时 25 分 | 0.05 秒 | 460,000× | - | 有索引列 | `CHAR(120) → VARCHAR(60)` | 7 小时 16 分 | 12 分 56 秒 | 34× | + | Scenario | Operation type | Before optimization | After optimization | Performance improvement | + |----------|----------------|---------------------|--------------------|--------------------------| + | Non-indexed column | `BIGINT → INT` | 2 hours 34 minutes | 1 minute 5 seconds | 142× faster | + | Indexed column | `BIGINT → INT` | 6 hours 25 minutes | 0.05 seconds | 460,000× faster | + | Indexed column | `CHAR(120) → VARCHAR(60)` | 7 hours 16 minutes | 12 minutes 56 seconds | 34× faster | - 注：以上数据基于 DDL 执行过程中未发生数据截断的前提。以上优化对于有 TiFlash 副本的表，以及符号类型转换场景（如 `Signed` ↔ `Unsigned`）场景不会生效。 + Note that the preceding test results are based on the condition that no data truncation occurs during the DDL execution. The optimizations do not apply to tables with TiFlash replicas or to schema changes involving conversions between signed and unsigned integer types (signed ↔ unsigned). - 更多信息，请参考[用户文档](链接)。 + For more information, see [documentation](/sql-statements/sql-statement-modify-column.md). * Improve DDL performance in scenarios with a large number of foreign keys, with up to a 25x increase in logical DDL performance [#61126](https://github.com/pingcap/tidb/issues/61126) @[GMHDBJD](https://github.com/GMHDBJD) **tw@hfxsd** From 79dc832caa3c5e2d7eebc0638f7d2bbf2d1c8cad Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Mon, 5 Jan 2026 11:09:29 +0800 Subject: [PATCH 23/45] translate two features --- releases/release-8.5.5.md | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 0a0a331960905..f7d67ce58c738 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -51,11 +51,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- For more information, see [documentation](https://docs.pingcap.com/tidb/stable/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855). -* 表级和分区级亲和性属性 AFFINITY [#9764](https://github.com/tikv/pd/issues/9764) @[lhy1024](https://github.com/lhy1024) **tw@qiancai** +* Support table-level data affinity to improve query performance (experimental) [#9764](https://github.com/tikv/pd/issues/9764) @[lhy1024](https://github.com/lhy1024) **tw@qiancai** - 为表或者分区表新增亲和性属性，设置亲和性属性后，PD会将表或分区的Region归为相同的一个亲和性分组中，这些Region的Leader、Voter 会被优先调度到指定TiKV Store上。有AFFNITY属性的表和分区在查询时，由于索引、表数据的Region都在一个TiKV Store上，因此优化器可结合 hint INDEX_LOOKUP_PUSHDOWN 指定将对应索引查询下推，减少跨节点分散查询带来的延迟，根据测试数据对比性能可约提升20%。 + Starting from v8.5.5, you can set the `AFFINITY` table option to `table` or `partition` when creating or altering a table. When this option is enabled, PD groups Regions that belong to the same table or the same partition into a single affinity group. During scheduling, PD preferentially places the Leaders and Voter replicas of these Regions on the same small set of TiKV nodes. In this scenario, by using the [`INDEX_LOOKUP_PUSHDOWN`](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855) hint in queries, you can explicitly instruct the optimizer to push index lookups down to TiKV, reducing the latency caused by cross-node scattered queries and improving query performance. - 更多信息，请参考[table-affinity.md](table-affinity.md)。 + Note that this feature is currently experimental and is disabled by default. To enable it, set the PD configuration item [`schedule.affinity-schedule-limit`](https://docs.pingcap.com/tidb/v8.5/pd-configuration-file#affinity-schedule-limit-new-in-v855) to a value greater than `0`. This configuration item controls the maximum number of affinity scheduling tasks that PD can perform concurrently. + + For more information, see [documentation](https://docs.pingcap.com/tidb/v8.5/table-affinity). * Point-in-time recovery (PITR) supports recovery from compacted log backups for faster restores [#56522](https://github.com/pingcap/tidb/issues/56522) @[YuJuncen](https://github.com/YuJuncen) **tw@lilin90** @@ -91,11 +93,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### SQL -* 支持在线修改分布式 ADD Index 任务的并发和吞吐 [#62120](https://github.com/pingcap/tidb/pull/62120) @[joechenrh](https://github.com/joechenrh) **tw@qiancai** +* Support dynamically modifying the concurrency and throughput of distributed `ADD INDEX` jobs [#62120](https://github.com/pingcap/tidb/pull/62120) @[joechenrh](https://github.com/joechenrh) **tw@qiancai** + + In TiDB versions earlier than v8.5.5, when the Distributed eXecution Framework (DXF) [`tidb_enable_dist_task`](/system-variables/#tidb_enable_dist_task-new-in-v710) is enabled, modifying the `THREAD`, `BATCH_SIZE`, or `MAX_WRITE_SPEED` parameters of a running `ADD INDEX` job is not supported. To change these parameters, you have to cancel the running `ADD INDEX` job, reconfigure the parameters, and then resubmit the job, which is inefficient. - 在 v8.5.5 版本之前，当集群开启了分布式执行框架 [tidb_enable_dist_task](/system-variables/#tidb_enable_dist_task-从-v710-版本开始引入) ，在 ADD Index 任务执行期间，是无法修改该任务的 `THREAD`， `BATCH_SIZE`，`MAX_WRITE_SPEED` 参数。需要取消该 DDL 任务，重新设置参数后再提交，效率较低。支持该功能后，用户可以根据业务负载和对 ADD Index 的性能要求，在线灵活调整这些参数。 + Starting from v8.5.5, you can use the `ADMIN ALTER DDL JOBS` statement to dynamically adjust these parameters of a running distributed `ADD INDEX` job based on the current workload and performance requirements, without interrupting the job. - 更多信息，请参考[ADMIN ALTER DDL JOBS](/sql-statement-admin-alter-ddl/#admin-alter-ddl-jobs)。 + For more information, see [documentation](/sql-statements/sql-statement-admin-alter-ddl.md). ### DB operations From 88ef8b10165b5777e861e52eeaa3d584c659efd9 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Mon, 5 Jan 2026 11:09:40 +0800 Subject: [PATCH 24/45] Update releases/release-8.5.5.md --- releases/release-8.5.5.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index f7d67ce58c738..cdf79bb54b1bc 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -20,7 +20,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- The optimization strategies are as follows: - In strict SQL mode, TiDB pre-checks for potential data truncation risks during type conversion. - - If no data truncation risk is detected, TiDB updates only the metadata and avoids index rebuilding whenever possible + - If no data truncation risk is detected, TiDB updates only the metadata and avoids index rebuilding whenever possible. - If index rebuilding is required, TiDB uses a more efficient ingest process to significantly improve index rebuild performance. The following table shows example performance improvements based on benchmark tests on a table with 114 GiB of data and 600 million rows. The test cluster consists of 3 TiDB nodes, 6 TiKV nodes, and 1 PD node. All nodes are configured with 16 CPU cores and 32 GiB of memory. From 3c342fb0a9e1988a3b75cdfce33f3d52f270ce8a Mon Sep 17 00:00:00 2001 From: Lilian Lee Date: Mon, 5 Jan 2026 11:12:07 +0800 Subject: [PATCH 25/45] Refine wording --- releases/release-8.5.5.md | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index cdf79bb54b1bc..2c7bc8addd38d 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -63,15 +63,15 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- Starting from v8.5.5, the log backup compaction feature provides offline compaction capabilities, converting unstructured log backup data into structured SST files. This results in the following improvements: - - **Improved recovery performance** - SST files can be more quickly imported into the cluster. - - **Reduced storage space consumption** - redundant data is removed during compaction. - - **Reduced impact on applications** - RPOs can be amintained with less frequent full snapshot-based backups. + - **Improved recovery performance**: SST files can be more quickly imported into the cluster. + - **Reduced storage space consumption**: redundant data is removed during compaction. + - **Reduced impact on applications**: RPOs (Recovery Point Objective) can be maintained with less frequent full snapshot-based backups. For more information, see [documentation](/br/br-compact-log-backup.md). -* Accelerated recovery of system tables from backups [#58757](https://github.com/pingcap/tidb/issues/58757) @[Leavrth](https://github.com/Leavrth) **tw@lilin90** +* Accelerate recovery of system tables from backups [#58757](https://github.com/pingcap/tidb/issues/58757) @[Leavrth](https://github.com/Leavrth) **tw@lilin90** - When restoring system tables from a backup, BR now introduces a new `--fast-load-sys-tables` parameter to use physical restoration instead of logical restoration. This option completely overwrites/replaces the existing tables, instead of restoring into them, for faster restoration for large scale deployments. + Starting from v8.5.5, for restoring system tables from a backup, BR introduces a new `--fast-load-sys-tables` parameter to use physical restore instead of logical restore. With this parameter enabled, BR fully replaces or overwrites the existing system tables rather than restoring data into them, significantly improving restore performance in large-scale deployments. For more information, see [Documentation](/br/br-snapshot-guide.md#restore-tables-in-the-mysql-schema). From cc56942a22a419c7aed2cc834be32d056c7ec073 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Mon, 5 Jan 2026 13:48:36 +0800 Subject: [PATCH 26/45] Update releases/release-8.5.5.md --- releases/release-8.5.5.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 2c7bc8addd38d..a40f2f5c47774 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -145,7 +145,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Enable Azure Managed Identity (MI) authentication for Backup & Restore (BR) to Azure Blob Storage [#19006](https://github.com/tikv/tikv/issues/19006) @[RidRisR](https://github.com/RidRisR) **tw@qiancai** - Starting from v8.5.5, BR supports Azure Managed Identity (MI) for authenticating to Azure Blob Storage, eliminating the need for static SAS tokens. This enables secure, keyless, and ephemeral authentication that follows Azure best practices. + Starting from v8.5.5, BR supports Azure Managed Identity (MI) for authenticating to Azure Blob Storage, eliminating the need for static SAS tokens. This enables secure, keyless, and ephemeral authentication that follows Azure security best practices. With this feature, BR and the embedded BR worker in TiKV can acquire access tokens directly from Azure Instance Metadata Service (IMDS), reducing credential leakage risk and simplifying credential rotation for self-managed and cloud deployments on Azure. From 842030e7428a2b09aada1a466e45b83093ba7d29 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Mon, 5 Jan 2026 13:49:37 +0800 Subject: [PATCH 27/45] Apply suggestions from code review --- releases/release-8.5.5.md | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index a40f2f5c47774..c7314f88e6ed0 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -17,23 +17,23 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Introduce significant performance improvements for certain lossy DDL operations (such as `BIGINT → INT` and `CHAR(120) → VARCHAR(60)`): when no data truncation occurs, the execution time of these operations can be reduced from hours to minutes, seconds, or even milliseconds, delivering performance gains ranging from tens to hundreds of thousands of times [#63366](https://github.com/pingcap/tidb/issues/63366) [@wjhuang2016](https://github.com/wjhuang2016), [@tangenta](https://github.com/tangenta), [@fzzf678](https://github.com/fzzf678) **tw@qiancai** - The optimization strategies are as follows: + The optimization strategies are as follows: - - In strict SQL mode, TiDB pre-checks for potential data truncation risks during type conversion. - - If no data truncation risk is detected, TiDB updates only the metadata and avoids index rebuilding whenever possible. - - If index rebuilding is required, TiDB uses a more efficient ingest process to significantly improve index rebuild performance. + - In strict SQL mode, TiDB pre-checks for potential data truncation risks during type conversion. + - If no data truncation risk is detected, TiDB updates only the metadata and avoids index rebuilding whenever possible. + - If index rebuilding is required, TiDB uses a more efficient ingest process to significantly improve index rebuild performance. - The following table shows example performance improvements based on benchmark tests on a table with 114 GiB of data and 600 million rows. The test cluster consists of 3 TiDB nodes, 6 TiKV nodes, and 1 PD node. All nodes are configured with 16 CPU cores and 32 GiB of memory. + The following table shows example performance improvements based on benchmark tests on a table with 114 GiB of data and 600 million rows. The test cluster consists of 3 TiDB nodes, 6 TiKV nodes, and 1 PD node. All nodes are configured with 16 CPU cores and 32 GiB of memory. - | Scenario | Operation type | Before optimization | After optimization | Performance improvement | - |----------|----------------|---------------------|--------------------|--------------------------| - | Non-indexed column | `BIGINT → INT` | 2 hours 34 minutes | 1 minute 5 seconds | 142× faster | - | Indexed column | `BIGINT → INT` | 6 hours 25 minutes | 0.05 seconds | 460,000× faster | - | Indexed column | `CHAR(120) → VARCHAR(60)` | 7 hours 16 minutes | 12 minutes 56 seconds | 34× faster | + | Scenario | Operation type | Before optimization | After optimization | Performance improvement | + |----------|----------------|---------------------|--------------------|--------------------------| + | Non-indexed column | `BIGINT → INT` | 2 hours 34 minutes | 1 minute 5 seconds | 142× faster | + | Indexed column | `BIGINT → INT` | 6 hours 25 minutes | 0.05 seconds | 460,000× faster | + | Indexed column | `CHAR(120) → VARCHAR(60)` | 7 hours 16 minutes | 12 minutes 56 seconds | 34× faster | - Note that the preceding test results are based on the condition that no data truncation occurs during the DDL execution. The optimizations do not apply to tables with TiFlash replicas or to schema changes involving conversions between signed and unsigned integer types (signed ↔ unsigned). + Note that the preceding test results are based on the condition that no data truncation occurs during the DDL execution. The optimizations do not apply to tables with TiFlash replicas or to schema changes involving conversions between signed and unsigned integer types (signed ↔ unsigned). - For more information, see [documentation](/sql-statements/sql-statement-modify-column.md). + For more information, see [documentation](/sql-statements/sql-statement-modify-column.md). * Improve DDL performance in scenarios with a large number of foreign keys, with up to a 25x increase in logical DDL performance [#61126](https://github.com/pingcap/tidb/issues/61126) @[GMHDBJD](https://github.com/GMHDBJD) **tw@hfxsd** @@ -103,11 +103,11 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### DB operations -* TiKV 支持优雅关闭 (graceful shutdown) [#17221](https://github.com/tikv/tikv/issues/17221) @[hujiatao0](https://github.com/hujiatao0) **tw@qiancai** +* Support gracefully shutting down TiKV [#17221](https://github.com/tikv/tikv/issues/17221) @[hujiatao0](https://github.com/hujiatao0) **tw@qiancai** - 在关闭 TiKV 服务器时，TiKV 会尽量将其上的 leader 副本转移到其他 TiKV 节点，然后再关闭。该等待期默认为 20 秒，可通过 [`server.graceful-shutdown-timeout`](https://docs.pingcap.com/zh/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-从-v855-版本开始引入) 配置项进行调整。若达到该超时时间后仍有 leader 未完成转移，TiKV 将跳过剩余 leader 的转移，直接进入关闭流程。 + When shutting down a TiKV server, TiKV attempts to transfer the Leader replicas on the node to other TiKV nodes within a configurable timeout duration before the shutdown. The default timeout duration is 20 seconds, and you can adjust it using the [`server.graceful-shutdown-timeout`](https://docs.pingcap.com/zh/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-new-in-v855) configuration item. If the timeout is reached and some Leaders have not been successfully transferred, TiKV skips the remaining Leader transfers and proceeds with the shutdown. - 更多信息，请参考[用户文档](https://docs.pingcap.com/zh/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-从-v855-版本开始引入)。 + For more information, see [documentation](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-new-in-v855). * Improve the compatibility between ongoing log backup and snapshot restore [#58685](https://github.com/pingcap/tidb/issues/58685) @[BornChanger](https://github.com/BornChanger) **tw@lilin90** From 0dda86799a6abf62742a41915b2f62824a597241 Mon Sep 17 00:00:00 2001 From: qiancai Date: Mon, 5 Jan 2026 14:31:55 +0800 Subject: [PATCH 28/45] add release notes from the zh PR --- releases/release-8.5.5.md | 132 ++++++++++++++------------------------ 1 file changed, 49 insertions(+), 83 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index c7314f88e6ed0..57ee6964668ad 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -186,9 +186,10 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiDB - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) -- improve the error message for import into when there are encoding errors [#issue](https://github.com/pingcap/tidb/issues/63763) @[D3Hunter](https://github.com/D3Hunter) -- change the parser for parquet format to get better performance [#issue](https://github.com/pingcap/tidb/issues/62906) @[joechenrh](https://github.com/joechenrh) + - improve the error message for import into when there are encoding errors [#63763](https://github.com/pingcap/tidb/issues/63763) @[D3Hunter](https://github.com/D3Hunter) + - change the parser for parquet format to get better performance [#62906](https://github.com/pingcap/tidb/issues/) @[joechenrh](https://github.com/joechenrh) + - 将 `tidb_analyze_column_options` 的默认值设置为 `all` [#64992](https://github.com/pingcap/tidb/issues/64992) @[0xPoe](https://github.com/0xPoe) + - 优化 IndexHashJoin 的执行方式，在部分 JOIN 场景下采用增量处理以避免一次性加载大量数据，显著降低内存占用并提升执行性能 [#63303](https://github.com/pingcap/tidb/issues/63303) @[ChangRui-Ryan](https://github.com/ChangRui-Ryan) - (dup): release-9.0.0.md > Improvements> TiDB - Optimize the CPU usage of internal SQL statements in the Distributed eXecution Framework (DXF) [#59344](https://github.com/pingcap/tidb/issues/59344) @[D3Hunter](https://github.com/D3Hunter) + TiKV @@ -200,66 +201,51 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + PD - - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - -+ TiFlash - - - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - 优化了高基数指标 [#9357](https://github.com/tikv/pd/issues/9357) @[rleungx](https://github.com/rleungx) + - 优化了时间戳推进和选举逻辑 [#9981](https://github.com/tikv/pd/issues/9981) @[bufferflies](https://github.com/bufferflies) + - 支持批量设置 TiKV 的 store limit [#9970](https://github.com/tikv/pd/issues/9970) @[bufferflies](https://github.com/bufferflies) + - `pd_cluster_status` 增加了 store 标签 [#9855](https://github.com/tikv/pd/issues/9855) @[SerjKol80](https://github.com/SerjKol80) + Tools - + Backup & Restore (BR) - - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - + TiCDC - Add more verification for the changefeed config when creating changefeed. [#12253](https://github.com/pingcap/tiflow/issues/12253) @[wk989898](https://github.com/wk989898) - + TiDB Data Migration (DM) - - - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - + TiDB Lightning - - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - + Dumpling - - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - + TiUP - - - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - ## Bug fixes + TiDB -- fix the problem that foreign key is not updated after modify column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) -- fix error decoding `RENAME TABLE` job arg from older version TiDB [#issue](https://github.com/pingcap/tidb/issues/64413) @[joechenrh](https://github.com/joechenrh) -- fix missing rebase auto increment not executed if BR restore failed [#issue](https://github.com/pingcap/tidb/issues/64761) @[joechenrh](https://github.com/joechenrh) -- fix OOM issue when querying `information_schema` tables [#issue](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) -- fix the problem that TiDB node may stuck during upgrade [#issue](https://github.com/pingcap/tidb/issues/64539) @[joechenrh](https://github.com/joechenrh) -- fix unexpected successful admin check when there are no index record [#issue](https://github.com/pingcap/tidb/issues/63698) @[wjhuang2016](https://github.com/wjhuang2016) -- fix data-index inconsistency when chaning collation with modify column [#issue](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) -- fix incorrect initialization for foreign key related fields when copying table info [#issue](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) -- fix the problem that embedded analyze may be not triggered for multi schema change [#issue](https://github.com/pingcap/tidb/issues/65040) @[joechenrh](https://github.com/joechenrh) -- fix the problem that the DXF task was not cancelled after canceling the add index job [#issue](https://github.com/pingcap/tidb/issues/64129) @[tangenta](https://github.com/tangenta) -- fix incorrect check to determing whether to load table info for tables contain foreign key [#issue](https://github.com/pingcap/tidb/issues/60444) @[JQWong7](https://github.com/JQWong7) -- fix incorrect auto ID setting after cross-database rename table [#issue](https://github.com/pingcap/tidb/issues/64561) @[joechenrh](https://github.com/joechenrh) -- fix incorrect handling meta key for older version of TiDB [#issue](https://github.com/pingcap/tidb/issues/64323) @[wjhuang2016](https://github.com/wjhuang2016) -- fix ligtning doesnt' report error for schema files without trailing semicolon [#issue](https://github.com/pingcap/tidb/issues/63414) @[GMHDBJD](https://github.com/GMHDBJD) -- fix the dead loop when reading files during IMPORT INTO global sort [#issue](https://github.com/pingcap/tidb/issues/61177) @[CbcWestwolf](https://github.com/CbcWestwolf) -- fix the panic when processing generated columns for IMPORT INTO [#issue](https://github.com/pingcap/tidb/issues/64657) @[D3Hunter](https://github.com/D3Hunter) - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - 修复 TiDB 初始化时无法读取最新的 tidb_mem_quota_binding_cache 变量值初始化 binding 的问题 [#65381](https://github.com/pingcap/tidb/issues/65381) @[qw4990](https://github.com/qw4990) + - 修复了在 `extractBestCNFItemRanges` 中错误地跳过候选项导致查询范围计算不精确的问题 [#62547](https://github.com/pingcap/tidb/issues/62547) @[hawkingrei](https://github.com/hawkingrei) + - 修复了 `plan replayer` 无法加载 binding 的问题 [#64811](https://github.com/pingcap/tidb/issues/64811) @[hawkingrei](https://github.com/hawkingrei) + - 修复了 `PointGet` 在有足够内存时仍不复用 chunk 导致不必要内存分配的问题 [#63920](https://github.com/pingcap/tidb/issues/63920) @[hawkingrei](https://github.com/hawkingrei) + - 修复了 `LogicalProjection.DeriveStats` 分配过多内存的问题 [#63810](https://github.com/pingcap/tidb/issues/63810) @[hawkingrei](https://github.com/hawkingrei) + - 修复了当查询发生 panic 时 `plan replayer` 无法 dump 的问题 [#64835](https://github.com/pingcap/tidb/issues/64835) @[hawkingrei](https://github.com/hawkingrei) + - 提升了 `expression.Contains` 函数的性能 [#61373](https://github.com/pingcap/tidb/issues/61373) @[hawkingrei](https://github.com/hawkingrei) + - 修复当计划缓存开启时，关联子查询可能产生非预期的全表扫描的问题 [#64645](https://github.com/pingcap/tidb/issues/64645) @[winoros](https://github.com/winoros) + - 修复系统表会污染表健康度监控的问题 [#57176](https://github.com/pingcap/tidb/issues/57176), [#64080](https://github.com/pingcap/tidb/issues/64080) @[0xPoe](https://github.com/0xPoe) + - 修复 auto-anlyze 关闭之后 `mysql.tidb_ddl_notifier` 不能被清理的问题 [#64038](https://github.com/pingcap/tidb/issues/64038) @[0xPoe](https://github.com/0xPoe) + - 修复了在 `newLocalColumnPool` 中重复分配 column 的问题 [#63809](https://github.com/pingcap/tidb/issues/63809) @[hawkingrei](https://github.com/hawkingrei) + - 减少无效的 sync load 加载失败警告日志 [#63880](https://github.com/pingcap/tidb/issues/63880) @[0xPoe](https://github.com/0xPoe) + - 修复手动 kill 正在执行事务的 connection 可能导致 tidb 发生 panic 异常退出的问题 [#63956](https://github.com/pingcap/tidb/issues/63956) @[wshwsh12](https://github.com/wshwsh12) + - 修复缓存表在走 TiFlash 副本读取时可能出现的 goroutine 和内存泄漏问题 [#63329](https://github.com/pingcap/tidb/issues/63329) @[xzhangxian1008](https://github.com/xzhangxian1008) + - fix the problem that foreign key is not updated after modify column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) + - fix error decoding `RENAME TABLE` job arg from older version TiDB [#issue](https://github.com/pingcap/tidb/issues/64413) @[joechenrh](https://github.com/joechenrh) + - fix missing rebase auto increment not executed if BR restore failed [#issue](https://github.com/pingcap/tidb/issues/64761) @[joechenrh](https://github.com/joechenrh) + - fix OOM issue when querying `information_schema` tables [#issue](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) + - fix the problem that TiDB node may stuck during upgrade [#issue](https://github.com/pingcap/tidb/issues/64539) @[joechenrh](https://github.com/joechenrh) + - fix unexpected successful admin check when there are no index record [#issue](https://github.com/pingcap/tidb/issues/63698) @[wjhuang2016](https://github.com/wjhuang2016) + - fix data-index inconsistency when chaning collation with modify column [#issue](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) + - fix incorrect initialization for foreign key related fields when copying table info [#issue](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) + - fix the problem that embedded analyze may be not triggered for multi schema change [#issue](https://github.com/pingcap/tidb/issues/65040) @[joechenrh](https://github.com/joechenrh) + - fix the problem that the DXF task was not cancelled after canceling the add index job [#issue](https://github.com/pingcap/tidb/issues/64129) @[tangenta](https://github.com/tangenta) + - fix incorrect check to determing whether to load table info for tables contain foreign key [#issue](https://github.com/pingcap/tidb/issues/60444) @[JQWong7](https://github.com/JQWong7) + - fix incorrect auto ID setting after cross-database rename table [#issue](https://github.com/pingcap/tidb/issues/64561) @[joechenrh](https://github.com/joechenrh) + - fix incorrect handling meta key for older version of TiDB [#issue](https://github.com/pingcap/tidb/issues/64323) @[wjhuang2016](https://github.com/wjhuang2016) + - fix ligtning doesnt' report error for schema files without trailing semicolon [#issue](https://github.com/pingcap/tidb/issues/63414) @[GMHDBJD](https://github.com/GMHDBJD) + - fix the dead loop when reading files during IMPORT INTO global sort [#issue](https://github.com/pingcap/tidb/issues/61177) @[CbcWestwolf](https://github.com/CbcWestwolf) + - fix the panic when processing generated columns for IMPORT INTO [#issue](https://github.com/pingcap/tidb/issues/64657) @[D3Hunter](https://github.com/D3Hunter) - (dup): release-9.0.0.md > Bug fixes> TiDB - Fix the potential OOM issue when querying `information_schema.tables` by improving memory usage monitoring when quering system tables [#58985](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) + TiKV @@ -274,19 +260,24 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + PD - - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/tikv/pd/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - 修复节点在上线过程中可能无法下线的问题 [#8997](https://github.com/tikv/pd/issues/8997) @[lhy1024](https://github.com/lhy1024) + - 修复因大量 leader transfer 可能导致 region size 跳变的问题 [#10014](https://github.com/tikv/pd/issues/10014) @[lhy1024](https://github.com/lhy1024) + - 修复调度过程中可能导致 PD panic 的问题 [#9951](https://github.com/tikv/pd/issues/9951) @[bufferflies](https://github.com/bufferflies) + - 修复导入过程中数据不均衡的问题 [#9088](https://github.com/tikv/pd/issues/9088) @[GMHDBJD](https://github.com/GMHDBJD) + - 修复开启 PD follower handle 后遇到错误时，无法将请求回退到 leader 处理的问题 [#64933](https://github.com/pingcap/tidb/issues/64933) @[okJiang](https://github.com/okJiang) + - 修复微服务请求没有正常转发的问题 [#9825](https://github.com/tikv/pd/issues/9825) @[lhy1024](https://github.com/lhy1024) [#9825](https://github.com/tikv/pd/issues/9825) @[lhy1024](https://github.com/lhy1024) + - 修复微服务 TLS 配置问题 [#9367](https://github.com/tikv/pd/issues/9367) @[rleungx](https://github.com/rleungx) + TiFlash - - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tiflash/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) + - 修复在 BR restore 的过程中，TiFlash 可能 panic 的问题 [#10606](https://github.com/pingcap/tiflash/issues/10606) @[CalvinNeo](https://github.com/CalvinNeo) + - 修复在 BR restore 的过程中，TiFlash 不能充分利用超过 16 核 CPU 进行数据恢复的问题 [#10605](https://github.com/pingcap/tiflash/issues/10605) @[JaySon-Huang](https://github.com/JaySon-Huang) + - 修复 GROUP_CONCAT 触发落盘时可能导致 TiFlash 异常退出的问题 [#10553](https://github.com/pingcap/tiflash/issues/10553) @[ChangRui-Ryan](https://github.com/ChangRui-Ryan) + Tools + Backup & Restore (BR) - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - Fixed an issue that memory usage may be unacceptable when log backup enabled and many regions in cluster. [#18719](https://github.com/tikv/tikv/issues/18719) @[YuJuncen](https://github.com/YuJuncen) - Fixed an issue that Azure SDK cannot found suitable key from environment. [#18206](https://github.com/tikv/tikv/issues/18206) @[YuJuncen](https://github.com/YuJuncen) - Fixed an issue that foreign keys cannot be properly fixed during `restore point`. [#61642](https://github.com/pingcap/tidb/issues/61642) @[Leavrth](https://github.com/Leavrth) @@ -301,30 +292,5 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - Fix the issue that causes the changefeed to fail when truncating partition tables [#12430](https://github.com/pingcap/tiflow/issues/12430) @[wk989898](https://github.com/wk989898) - Fix the incorrect execution order of split DDLs generated from a multi-table DDL statement [#12449](https://github.com/pingcap/tiflow/issues/12449) @[wlwilliamx](https://github.com/wlwilliamx) - Upgrade aws-sdk-go-v2 dependency to fix glue schema registry[#12424](https://github.com/pingcap/tiflow/issues/12424) @[wk989898](https://github.com/wk989898) - - Fix the issue that may cause the sink memory quota not to be released [#18169](https://github.com/tikv/tikv/issues/18169) @[asddongmen](https://github.com/asddongmen) + - Fix the issue that may cause the sink memory quota not to be released [#18169](https://github.com/tikv/tikv/issues/18169) @[asddongmen](https://github.com/asddongmen) - Fix the issue that may cause the sink memory quota not to be released [#18915](https://github.com/tikv/tikv/issues/18915) @[asddongmen](https://github.com/asddongmen) - - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - + TiDB Data Migration (DM) - - - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tiflow/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - + TiDB Lightning - - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - + Dumpling - - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tidb/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - + TiUP - - - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - - note [#issue](https://github.com/pingcap/tiup/issues/${issue-id}) @[Contributor GitHub ID](https://github.com/${github-id}) - -## Other dup notes - -- (dup): release-9.0.0.md > # Observability * Add storage engine identifiers to statement summary tables and slow query logs [#61736](https://github.com/pingcap/tidb/issues/61736) @[henrybw](https://github.com/henrybw) **tw@Oreoxmt** From 52eb72a6280b2ca9e5cbf829919773f5969a698e Mon Sep 17 00:00:00 2001 From: qiancai Date: Mon, 5 Jan 2026 14:35:11 +0800 Subject: [PATCH 29/45] add tw info for improvements and bug fixes --- releases/release-8.5.5.md | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 57ee6964668ad..473da4b8b20ec 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -184,7 +184,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ## Improvements -+ TiDB ++ TiDB - improve the error message for import into when there are encoding errors [#63763](https://github.com/pingcap/tidb/issues/63763) @[D3Hunter](https://github.com/D3Hunter) - change the parser for parquet format to get better performance [#62906](https://github.com/pingcap/tidb/issues/) @[joechenrh](https://github.com/joechenrh) @@ -192,14 +192,14 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - 优化 IndexHashJoin 的执行方式，在部分 JOIN 场景下采用增量处理以避免一次性加载大量数据，显著降低内存占用并提升执行性能 [#63303](https://github.com/pingcap/tidb/issues/63303) @[ChangRui-Ryan](https://github.com/ChangRui-Ryan) - (dup): release-9.0.0.md > Improvements> TiDB - Optimize the CPU usage of internal SQL statements in the Distributed eXecution Framework (DXF) [#59344](https://github.com/pingcap/tidb/issues/59344) @[D3Hunter](https://github.com/D3Hunter) -+ TiKV ++ TiKV - Introduces CPU-aware scaling for the unified read pool to avoid CPU starvation under hot read workloads. [#18464](https://github.com/tikv/tikv/issues/18464) @[mittalrishabh](https://github.com/mittalrishabh) - Adds network latency awareness to slow score to avoid scheduling leaders on TiKV nodes with unstable network conditions. [#18797](https://github.com/tikv/tikv/issues/18797) @[okJiang](https://github.com/okJiang) - Optimizes hibernate behavior by allowing leaders to enter hibernation once a majority vote is reached, without waiting for down non-voter peers. [#19070](https://github.com/tikv/tikv/issues/19070) @[jiadebin](https://github.com/jiadebin) - (dup): release-9.0.0.md > Improvements> TiKV - Throttle BR log restore requests when TiKV memory usage is high to prevent TiKV OOM [#18124](https://github.com/tikv/tikv/issues/18124) @[3pointer](https://github.com/3pointer) -+ PD ++ PD - 优化了高基数指标 [#9357](https://github.com/tikv/pd/issues/9357) @[rleungx](https://github.com/rleungx) - 优化了时间戳推进和选举逻辑 [#9981](https://github.com/tikv/pd/issues/9981) @[bufferflies](https://github.com/bufferflies) @@ -208,13 +208,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + Tools - + TiCDC + + TiCDC - Add more verification for the changefeed config when creating changefeed. [#12253](https://github.com/pingcap/tiflow/issues/12253) @[wk989898](https://github.com/wk989898) ## Bug fixes -+ TiDB ++ TiDB - 修复 TiDB 初始化时无法读取最新的 tidb_mem_quota_binding_cache 变量值初始化 binding 的问题 [#65381](https://github.com/pingcap/tidb/issues/65381) @[qw4990](https://github.com/qw4990) - 修复了在 `extractBestCNFItemRanges` 中错误地跳过候选项导致查询范围计算不精确的问题 [#62547](https://github.com/pingcap/tidb/issues/62547) @[hawkingrei](https://github.com/hawkingrei) @@ -230,7 +230,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - 减少无效的 sync load 加载失败警告日志 [#63880](https://github.com/pingcap/tidb/issues/63880) @[0xPoe](https://github.com/0xPoe) - 修复手动 kill 正在执行事务的 connection 可能导致 tidb 发生 panic 异常退出的问题 [#63956](https://github.com/pingcap/tidb/issues/63956) @[wshwsh12](https://github.com/wshwsh12) - 修复缓存表在走 TiFlash 副本读取时可能出现的 goroutine 和内存泄漏问题 [#63329](https://github.com/pingcap/tidb/issues/63329) @[xzhangxian1008](https://github.com/xzhangxian1008) - - fix the problem that foreign key is not updated after modify column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) + - fix the problem that foreign key is not updated after modify column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) - fix error decoding `RENAME TABLE` job arg from older version TiDB [#issue](https://github.com/pingcap/tidb/issues/64413) @[joechenrh](https://github.com/joechenrh) - fix missing rebase auto increment not executed if BR restore failed [#issue](https://github.com/pingcap/tidb/issues/64761) @[joechenrh](https://github.com/joechenrh) - fix OOM issue when querying `information_schema` tables [#issue](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) @@ -248,7 +248,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - fix the panic when processing generated columns for IMPORT INTO [#issue](https://github.com/pingcap/tidb/issues/64657) @[D3Hunter](https://github.com/D3Hunter) - (dup): release-9.0.0.md > Bug fixes> TiDB - Fix the potential OOM issue when querying `information_schema.tables` by improving memory usage monitoring when quering system tables [#58985](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) -+ TiKV ++ TiKV - Fix the bug that analyze scan kv operation metric is always 0 [#19206](https://github.com/tikv/tikv/issues/19206) @[glorv](https://github.com/glorv) - Fix the bug that pd heartbeat may report wrong region size/keys statistics data after leader change. [#19180](https://github.com/tikv/tikv/issues/19180) @[glorv](https://github.com/glorv) @@ -258,7 +258,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - Fix the bug that pd heartbeat may report wrong region size/keys statistics data after leader change. [#19180](https://github.com/tikv/tikv/issues/19180) @[glorv](https://github.com/glorv) - Fixes a corner case where Raft peers could enter hibernation prematurely, causing them to remain busy and block leader transfers after TiKV restart. [#19203](https://github.com/tikv/tikv/issues/19203) @[LykxSassinator](https://github.com/LykxSassinator) -+ PD ++ PD - 修复节点在上线过程中可能无法下线的问题 [#8997](https://github.com/tikv/pd/issues/8997) @[lhy1024](https://github.com/lhy1024) - 修复因大量 leader transfer 可能导致 region size 跳变的问题 [#10014](https://github.com/tikv/pd/issues/10014) @[lhy1024](https://github.com/lhy1024) @@ -268,7 +268,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - 修复微服务请求没有正常转发的问题 [#9825](https://github.com/tikv/pd/issues/9825) @[lhy1024](https://github.com/lhy1024) [#9825](https://github.com/tikv/pd/issues/9825) @[lhy1024](https://github.com/lhy1024) - 修复微服务 TLS 配置问题 [#9367](https://github.com/tikv/pd/issues/9367) @[rleungx](https://github.com/rleungx) -+ TiFlash ++ TiFlash - 修复在 BR restore 的过程中，TiFlash 可能 panic 的问题 [#10606](https://github.com/pingcap/tiflash/issues/10606) @[CalvinNeo](https://github.com/CalvinNeo) - 修复在 BR restore 的过程中，TiFlash 不能充分利用超过 16 核 CPU 进行数据恢复的问题 [#10605](https://github.com/pingcap/tiflash/issues/10605) @[JaySon-Huang](https://github.com/JaySon-Huang) @@ -276,7 +276,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + Tools - + Backup & Restore (BR) + + Backup & Restore (BR) - Fixed an issue that memory usage may be unacceptable when log backup enabled and many regions in cluster. [#18719](https://github.com/tikv/tikv/issues/18719) @[YuJuncen](https://github.com/YuJuncen) - Fixed an issue that Azure SDK cannot found suitable key from environment. [#18206](https://github.com/tikv/tikv/issues/18206) @[YuJuncen](https://github.com/YuJuncen) @@ -286,7 +286,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - Fixed an issue that Azure managed identity is unavailable.[#19006](https://github.com/tikv/tikv/issues/19006) @[RidRisR](https://github.com/RidRisR) - Fixed an issue that may cause `restore point` from checkpoint panic when the log backup was mixed with a full backup. [#58685](https://github.com/pingcap/tidb/issues/58685) @[YuJuncen](https://github.com/YuJuncen) - + TiCDC + + TiCDC - Fix the issue that may cause DML loss while failing to close the writer of the storage sink [#12436](https://github.com/pingcap/tiflow/issues/12436) @[wk989898](https://github.com/wk989898) - Fix the issue that causes the changefeed to fail when truncating partition tables [#12430](https://github.com/pingcap/tiflow/issues/12430) @[wk989898](https://github.com/wk989898) From 13a437888a1d9f3cc2e357ed0c30347d93999a9b Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Mon, 5 Jan 2026 15:09:36 +0800 Subject: [PATCH 30/45] add a bug fix for TiDB --- releases/release-8.5.5.md | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 473da4b8b20ec..b1bcbf7844f85 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -230,7 +230,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - 减少无效的 sync load 加载失败警告日志 [#63880](https://github.com/pingcap/tidb/issues/63880) @[0xPoe](https://github.com/0xPoe) - 修复手动 kill 正在执行事务的 connection 可能导致 tidb 发生 panic 异常退出的问题 [#63956](https://github.com/pingcap/tidb/issues/63956) @[wshwsh12](https://github.com/wshwsh12) - 修复缓存表在走 TiFlash 副本读取时可能出现的 goroutine 和内存泄漏问题 [#63329](https://github.com/pingcap/tidb/issues/63329) @[xzhangxian1008](https://github.com/xzhangxian1008) - - fix the problem that foreign key is not updated after modify column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) + - fix the problem that foreign key is not updated after modify column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) - fix error decoding `RENAME TABLE` job arg from older version TiDB [#issue](https://github.com/pingcap/tidb/issues/64413) @[joechenrh](https://github.com/joechenrh) - fix missing rebase auto increment not executed if BR restore failed [#issue](https://github.com/pingcap/tidb/issues/64761) @[joechenrh](https://github.com/joechenrh) - fix OOM issue when querying `information_schema` tables [#issue](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) @@ -246,6 +246,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - fix ligtning doesnt' report error for schema files without trailing semicolon [#issue](https://github.com/pingcap/tidb/issues/63414) @[GMHDBJD](https://github.com/GMHDBJD) - fix the dead loop when reading files during IMPORT INTO global sort [#issue](https://github.com/pingcap/tidb/issues/61177) @[CbcWestwolf](https://github.com/CbcWestwolf) - fix the panic when processing generated columns for IMPORT INTO [#issue](https://github.com/pingcap/tidb/issues/64657) @[D3Hunter](https://github.com/D3Hunter) + - 修复在一个语句中有多个 `AS OF TIMESTAMP` 表达式时可能误报错的问题 [#issue](https://github.com/pingcap/tidb/issues/65090) @[you06](https://github.com/you06) - (dup): release-9.0.0.md > Bug fixes> TiDB - Fix the potential OOM issue when querying `information_schema.tables` by improving memory usage monitoring when quering system tables [#58985](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) + TiKV From b47208e25cad1a50e4a49ca9da1d05f29bb8d092 Mon Sep 17 00:00:00 2001 From: Ben Meadowcroft Date: Tue, 6 Jan 2026 10:14:06 -0800 Subject: [PATCH 31/45] Apply suggestions from code review Co-authored-by: Lilian Lee --- releases/release-8.5.5.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index b1bcbf7844f85..f10928ce9f65b 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -111,13 +111,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Improve the compatibility between ongoing log backup and snapshot restore [#58685](https://github.com/pingcap/tidb/issues/58685) @[BornChanger](https://github.com/BornChanger) **tw@lilin90** - Starting from v8.5.5, log backups can continue to run when performing a snapshot restore (when prerequisite conditions are met). This enables ongoing log backups to proceed without having to stop them during the restore procedure. The newly restored data will also be recorded in the ongoing log backup. + Starting from v8.5.5, when a log backup task is running, you can still perform a snapshot restore as long as prerequisite conditions are met. This enables ongoing log backups to proceed without having to stop them during the restore process, and the restored data is properly recorded by the ongoing log backup. For more information, see [documentation](https://docs.pingcap.com/tidb/v8.5/br-pitr-manual#compatibility-between-ongoing-log-backup-and-snapshot-restore). -* Table level restores from Log Backups [#57613](https://github.com/pingcap/tidb/issues/57613) @[Tristan1900](https://github.com/Tristan1900) **tw@lilin90** +* Support table-level restores from log backups [#57613](https://github.com/pingcap/tidb/issues/57613) @[Tristan1900](https://github.com/Tristan1900) **tw@lilin90** - Starting from v8.5.5, individual table level point in time recoveries can now be performed from log backups using filters. Being able to restore individual tables, instead of the full cluster, to a specific point in time enables much more flexible, and less impactful, recovery options. + Starting from v8.5.5, you can perform point-in-time recovery (PITR) for individual tables from log backups by using filters. Restoring specific tables, rather than the entire cluster, to a target point in time provides more flexible and less disruptive recovery options. For more information, see [documentation](/br/br-pitr-manual.md#restore-data-using-filters). From bdb4236693a0cd6dd17c3f9a4f611dc6aea38c7c Mon Sep 17 00:00:00 2001 From: qiancai Date: Wed, 7 Jan 2026 14:56:03 +0800 Subject: [PATCH 32/45] add parameter changes --- releases/release-8.5.5.md | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index f10928ce9f65b..6d397138d0e7f 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -105,7 +105,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Support gracefully shutting down TiKV [#17221](https://github.com/tikv/tikv/issues/17221) @[hujiatao0](https://github.com/hujiatao0) **tw@qiancai** - When shutting down a TiKV server, TiKV attempts to transfer the Leader replicas on the node to other TiKV nodes within a configurable timeout duration before the shutdown. The default timeout duration is 20 seconds, and you can adjust it using the [`server.graceful-shutdown-timeout`](https://docs.pingcap.com/zh/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-new-in-v855) configuration item. If the timeout is reached and some Leaders have not been successfully transferred, TiKV skips the remaining Leader transfers and proceeds with the shutdown. + When shutting down a TiKV server, TiKV attempts to transfer the Leader replicas on the node to other TiKV nodes within a configurable timeout duration before the shutdown. The default timeout duration is 20 seconds, and you can adjust it using the [`server.graceful-shutdown-timeout`](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-new-in-v855) configuration item. If the timeout is reached and some Leaders have not been successfully transferred, TiKV skips the remaining Leader transfers and proceeds with the shutdown. For more information, see [documentation](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-new-in-v855). @@ -174,9 +174,14 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- | Configuration file or component | Configuration parameter | Change type | Description | | -------- | -------- | -------- | -------- | -| | | | | -| | | | | -| | | | | +| PD | [`schedule.max-affinity-merge-region-size`](https://docs.pingcap.com/tidb/v8.5/pd-configuration-file#max-affinity-merge-region-size-new-in-v855) | Newly added | Controls the threshold for automatically merging adjacent small Regions within the same [affinity group](https://docs.pingcap.com/tidb/v8.5/table-affinity). The default value is `256`, in MiB. | +| PD | [`schedule.affinity-schedule-limit`](https://docs.pingcap.com/tidb/v8.5/pd-configuration-file#affinity-schedule-limit-new-in-v855) | Newly added | Controls the number of [affinity](https://docs.pingcap.com/tidb/v8.5/table-affinity) scheduling tasks that can be performed concurrently. The default value is `0`, which means that affinity scheduling is disabled by default. | +| TiKV | [`performance.enable-async-batch-get`](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#enable-async-batch-get-new-in-v855) | Newly added | Controls whether TiDB uses asynchronous mode to execute the Batch Get operator. The default value is `true`. | +| TiKV | [`server.graceful-shutdown-timeout`](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-new-in-v855) | Newly added | Controls the timeout duration for graceful shutdown of TiKV. The default value is `20s`. | +| TiKV | [`server.inspect-network-interval`](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#inspect-network-interval-new-in-v855) | Newly added | Controls the interval at which the TiKV HealthChecker actively performs network detection to PD and other TiKV nodes. The default value is `100ms`. | +| BR | [`--checkpoint-storage`](/br/br-checkpoint-restore.md#implementation-details-store-checkpoint-data-in-the-downstream-cluster) | Newly added | Specifies an external storage for checkpoint data. | +| BR | [`--fast-load-sys-tables`](/br/br-snapshot-guide.md#restore-tables-in-the-mysql-schema) | Newly added | Supports physical restore of system tables on a new cluster. This parameter is enabled by default. | +| BR | [`--filter`](/br/br-pitr-manual.md#restore-data-using-filters) | Newly added | Specifies patterns to include or exclude specific databases or tables for restore. | ### System tables From d17f085d0a92d7a834ef5f19ff5dd2e7e9465f77 Mon Sep 17 00:00:00 2001 From: qiancai Date: Wed, 7 Jan 2026 15:21:09 +0800 Subject: [PATCH 33/45] add links to variables --- releases/release-8.5.5.md | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 6d397138d0e7f..d0d360f822444 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -45,11 +45,11 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- Starting from v8.5.5, TiDB supports using optimizer hints to push the `IndexLookUp` operator down to TiKV nodes. This reduces the number of remote procedure calls (RPCs) and can improve query performance. The actual performance improvement varies depending on the specific workload and requires testing for verification. - You can use the [`INDEX_LOOKUP_PUSHDOWN(t1_name, idx1_name [, idx2_name ...])`](https://docs.pingcap.com/tidb/stable/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855) hint to explicitly instruct the optimizer to push index lookups down to TiKV for a specific table. It is recommended to combine this hint with the table's AFFINITY attribute. For example, set `AFFINITY="table"` for regular tables and `AFFINITY="partition"` for partitioned tables. + You can use the [`INDEX_LOOKUP_PUSHDOWN(t1_name, idx1_name [, idx2_name ...])`](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855) hint to explicitly instruct the optimizer to push index lookups down to TiKV for a specific table. It is recommended to combine this hint with the table's AFFINITY attribute. For example, set `AFFINITY="table"` for regular tables and `AFFINITY="partition"` for partitioned tables. - To disable index lookup pushdown to TiKV for a specific table, use the [`NO_INDEX_LOOKUP_PUSHDOWN(t1_name)`](https://docs.pingcap.com/tidb/stable/optimizer-hints#no_index_lookup_pushdownt1_name--new-in-v855) hint. + To disable index lookup pushdown to TiKV for a specific table, use the [`NO_INDEX_LOOKUP_PUSHDOWN(t1_name)`](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#no_index_lookup_pushdownt1_name--new-in-v855) hint. - For more information, see [documentation](https://docs.pingcap.com/tidb/stable/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855). + For more information, see [documentation](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855). * Support table-level data affinity to improve query performance (experimental) [#9764](https://github.com/tikv/pd/issues/9764) @[lhy1024](https://github.com/lhy1024) **tw@qiancai** @@ -165,10 +165,9 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- | Variable name | Change type | Description | |--------|------------------------------|------| -| `tidb_advancer_check_point_lag_limit` | Newly added | Controls the maximum allowed checkpoint lag for a log backup task. If a task's checkpoint lag exceeds this limit, TiDB Advancer pauses the task. | -| `tidb_cb_pd_metadata_error_rate_threshold_ratio` | Newly added | Controls when TiDB triggers the circuit breaker. Setting a value of `0` (default) disables the circuit breaker. Setting a value between `0.01` and `1` enables it, causing the circuit breaker to trigger when the error rate of specific requests sent to PD reaches or exceeds the threshold. | -| `tidb_index_lookup_pushdown_policy` | Newly added | Controls whether and when TiDB pushes the `IndexLookUp` operator down to TiKV. | -| | | | +| [`tidb_advancer_check_point_lag_limit`](https://docs.pingcap.com/tidb/v8.5/system-variables#tidb_advancer_check_point_lag_limit-new-in-v855) | Newly added | Controls the maximum allowed checkpoint lag for a log backup task. The default value is `48h0m0s`. If a task's checkpoint lag exceeds this limit, TiDB Advancer pauses the task. | +| [`tidb_cb_pd_metadata_error_rate_threshold_ratio`](https://docs.pingcap.com/tidb/v8.5/system-variables#tidb_cb_pd_metadata_error_rate_threshold_ratio-new-in-v855) | Newly added | Controls when TiDB triggers the circuit breaker. The default value is `0`, which means the circuit breaker is disabled. Setting a value between `0.01` and `1` enables it, causing the circuit breaker to trigger when the error rate of specific requests sent to PD reaches or exceeds the threshold. | +| [`tidb_index_lookup_pushdown_policy`](https://docs.pingcap.com/tidb/v8.5/system-variables#tidb_index_lookup_pushdown_policy-new-in-v855) | Newly added | Controls whether and when TiDB pushes the `IndexLookUp` operator down to TiKV. The default value is `hint-only`, which means TiDB pushes the `IndexLookUp` operator down to TiKV only when the [`INDEX_LOOKUP_PUSHDOWN`](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855) hint is explicitly specified in the SQL statement. | ### Configuration parameters From d9f1ac3abcec955edebe6e3f7501779624e5d2da Mon Sep 17 00:00:00 2001 From: Aolin Date: Wed, 7 Jan 2026 16:54:34 +0800 Subject: [PATCH 34/45] update PD, TiKV, BR --- releases/release-8.5.5.md | 35 +++++++++++++++++------------------ 1 file changed, 17 insertions(+), 18 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index d0d360f822444..d5c160d7a28a7 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -205,10 +205,10 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + PD - - 优化了高基数指标 [#9357](https://github.com/tikv/pd/issues/9357) @[rleungx](https://github.com/rleungx) - - 优化了时间戳推进和选举逻辑 [#9981](https://github.com/tikv/pd/issues/9981) @[bufferflies](https://github.com/bufferflies) - - 支持批量设置 TiKV 的 store limit [#9970](https://github.com/tikv/pd/issues/9970) @[bufferflies](https://github.com/bufferflies) - - `pd_cluster_status` 增加了 store 标签 [#9855](https://github.com/tikv/pd/issues/9855) @[SerjKol80](https://github.com/SerjKol80) + - Optimize metrics with high cardinality [#9357](https://github.com/tikv/pd/issues/9357) @[rleungx](https://github.com/rleungx) + - Optimize the logic for timestamp advancement and leader election [#9981](https://github.com/tikv/pd/issues/9981) @[bufferflies](https://github.com/bufferflies) + - Support batch configuration of TiKV store limits [#9970](https://github.com/tikv/pd/issues/9970) @[bufferflies](https://github.com/bufferflies) + - Add the `store` label to the `pd_cluster_status` metric [#9855](https://github.com/tikv/pd/issues/9855) @[SerjKol80](https://github.com/SerjKol80) + Tools @@ -255,13 +255,12 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiKV - - Fix the bug that analyze scan kv operation metric is always 0 [#19206](https://github.com/tikv/tikv/issues/19206) @[glorv](https://github.com/glorv) - - Fix the bug that pd heartbeat may report wrong region size/keys statistics data after leader change. [#19180](https://github.com/tikv/tikv/issues/19180) @[glorv](https://github.com/glorv) - - Fixes unsafe recovery getting stuck by removing tombstoned TiFlash learners from the unsafe recovery demotion list. [#18458](https://github.com/tikv/tikv/issues/18458) @[v01dstar](https://github.com/v01dstar) - - Fixes an issue where snapshots could be canceled indefinitely under continuous writes, blocking replica recovery. [#18872](https://github.com/tikv/tikv/issues/18872) @[exit-code-1](https://github.com/exit-code-1) - - Fixes compaction slowdowns caused by increased flow-control thresholds. [#18708](https://github.com/tikv/tikv/issues/18708) @[hhwyt](https://github.com/hhwyt) - - Fix the bug that pd heartbeat may report wrong region size/keys statistics data after leader change. [#19180](https://github.com/tikv/tikv/issues/19180) @[glorv](https://github.com/glorv) - - Fixes a corner case where Raft peers could enter hibernation prematurely, causing them to remain busy and block leader transfers after TiKV restart. [#19203](https://github.com/tikv/tikv/issues/19203) @[LykxSassinator](https://github.com/LykxSassinator) + - Fix the issue that the `KV Cursor Operations` metric for analyze requests is always `0` [#19206](https://github.com/tikv/tikv/issues/19206) @[glorv](https://github.com/glorv) + - Fix the issue that PD heartbeats might report incorrect Region size or key statistics after a leader change [#19180](https://github.com/tikv/tikv/issues/19180) @[glorv](https://github.com/glorv) + - Fix the issue that unsafe recovery gets stuck by removing tombstone TiFlash learners from the unsafe recovery demotion list [#18458](https://github.com/tikv/tikv/issues/18458) @[v01dstar](https://github.com/v01dstar) + - Fix the issue that snapshots might be canceled indefinitely during continuous writes, which blocks replica recovery [#18872](https://github.com/tikv/tikv/issues/18872) @[exit-code-1](https://github.com/exit-code-1) + - Fix the issue that compaction slows down due to increased flow-control thresholds [#18708](https://github.com/tikv/tikv/issues/18708) @[hhwyt](https://github.com/hhwyt) + - Fix the issue that Raft peers might enter hibernation prematurely in a corner case, causing them to remain busy and block leader transfers after a TiKV restart [#19203](https://github.com/tikv/tikv/issues/19203) @[LykxSassinator](https://github.com/LykxSassinator) + PD @@ -283,13 +282,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + Backup & Restore (BR) - - Fixed an issue that memory usage may be unacceptable when log backup enabled and many regions in cluster. [#18719](https://github.com/tikv/tikv/issues/18719) @[YuJuncen](https://github.com/YuJuncen) - - Fixed an issue that Azure SDK cannot found suitable key from environment. [#18206](https://github.com/tikv/tikv/issues/18206) @[YuJuncen](https://github.com/YuJuncen) - - Fixed an issue that foreign keys cannot be properly fixed during `restore point`. [#61642](https://github.com/pingcap/tidb/issues/61642) @[Leavrth](https://github.com/Leavrth) - - Fixed an issue that restore cannot be performed if system table collations are incompatible between backup and target cluster by introducing the parameter --sys-check-collation to support restore privileges tables from v6.5 to v7.5 [#64667](https://github.com/pingcap/tidb/issues/64667) @[Leavrth](https://github.com/Leavrth) - - Fixed an issue that caused `restore log` cannot be performed after a failed `restore point` though the latter is safe to be execued. [#64908](https://github.com/pingcap/tidb/issues/64908) @[RidRisR](https://github.com/RidRisR) - - Fixed an issue that Azure managed identity is unavailable.[#19006](https://github.com/tikv/tikv/issues/19006) @[RidRisR](https://github.com/RidRisR) - - Fixed an issue that may cause `restore point` from checkpoint panic when the log backup was mixed with a full backup. [#58685](https://github.com/pingcap/tidb/issues/58685) @[YuJuncen](https://github.com/YuJuncen) + - Fix the issue that enabling log backup causes excessive memory usage when the cluster contains many Regions [#18719](https://github.com/tikv/tikv/issues/18719) @[YuJuncen](https://github.com/YuJuncen) + - Fix the issue that the Azure SDK cannot find a suitable key from the environment [#18206](https://github.com/tikv/tikv/issues/18206) @[YuJuncen](https://github.com/YuJuncen) + - Fix the issue that foreign keys cannot be properly restored during `restore point` [#61642](https://github.com/pingcap/tidb/issues/61642) @[Leavrth](https://github.com/Leavrth) + - Fix the issue that restore fails if system table collations are incompatible between the backup and target cluster by adding the `--sys-check-collation` parameter to support restoring privilege tables from v6.5 to v7.5 [#64667](https://github.com/pingcap/tidb/issues/64667) @[Leavrth](https://github.com/Leavrth) + - Fix the issue that `restore log` cannot be performed after a failed `restore point`, even when the operation is safe [#64908](https://github.com/pingcap/tidb/issues/64908) @[RidRisR](https://github.com/RidRisR) + - Fix the issue that Azure Managed Identity is unavailable [#19006](https://github.com/tikv/tikv/issues/19006) @[RidRisR](https://github.com/RidRisR) + - Fix the issue that `restore point` from a checkpoint might panic when log backup data is mixed with a full backup [#58685](https://github.com/pingcap/tidb/issues/58685) @[YuJuncen](https://github.com/YuJuncen) + TiCDC From 1c3ddd3136f5c0e79b04c1f86fd926f85005232d Mon Sep 17 00:00:00 2001 From: xixirangrang Date: Thu, 8 Jan 2026 10:27:50 +0800 Subject: [PATCH 35/45] Update releases/release-8.5.5.md --- releases/release-8.5.5.md | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index d5c160d7a28a7..3b31554459b78 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -234,23 +234,23 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - 减少无效的 sync load 加载失败警告日志 [#63880](https://github.com/pingcap/tidb/issues/63880) @[0xPoe](https://github.com/0xPoe) - 修复手动 kill 正在执行事务的 connection 可能导致 tidb 发生 panic 异常退出的问题 [#63956](https://github.com/pingcap/tidb/issues/63956) @[wshwsh12](https://github.com/wshwsh12) - 修复缓存表在走 TiFlash 副本读取时可能出现的 goroutine 和内存泄漏问题 [#63329](https://github.com/pingcap/tidb/issues/63329) @[xzhangxian1008](https://github.com/xzhangxian1008) - - fix the problem that foreign key is not updated after modify column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) - - fix error decoding `RENAME TABLE` job arg from older version TiDB [#issue](https://github.com/pingcap/tidb/issues/64413) @[joechenrh](https://github.com/joechenrh) - - fix missing rebase auto increment not executed if BR restore failed [#issue](https://github.com/pingcap/tidb/issues/64761) @[joechenrh](https://github.com/joechenrh) - - fix OOM issue when querying `information_schema` tables [#issue](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) - - fix the problem that TiDB node may stuck during upgrade [#issue](https://github.com/pingcap/tidb/issues/64539) @[joechenrh](https://github.com/joechenrh) - - fix unexpected successful admin check when there are no index record [#issue](https://github.com/pingcap/tidb/issues/63698) @[wjhuang2016](https://github.com/wjhuang2016) - - fix data-index inconsistency when chaning collation with modify column [#issue](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) + - Fix the issue that foreign key is not updated after running `ALTER TABLE child CHANGE COLUMN` to modify a column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) + - Fix the issue that an error occurs when decoding the `RENAME TABLE` job arg from an earlier version [#64413](https://github.com/pingcap/tidb/issues/64413) @[joechenrh](https://github.com/joechenrh) + - Fix missing rebase auto increment not executed if BR restore failed [#64761](https://github.com/pingcap/tidb/issues/64761) @[joechenrh](https://github.com/joechenrh) + - Fix the OOM issue when querying `information_schema` tables [#58985](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) + - Fix the isse that the TiDB node might get stuck during upgrade [#64539](https://github.com/pingcap/tidb/issues/64539) @[joechenrh](https://github.com/joechenrh) + - Fix the issue that admin check does not report errors when there are no index records [#63698](https://github.com/pingcap/tidb/issues/63698) @[wjhuang2016](https://github.com/wjhuang2016) + - Fix the issue that data indexes are inconsistent when changing the collation with modify column [#61668](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) - fix incorrect initialization for foreign key related fields when copying table info [#issue](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) - - fix the problem that embedded analyze may be not triggered for multi schema change [#issue](https://github.com/pingcap/tidb/issues/65040) @[joechenrh](https://github.com/joechenrh) - - fix the problem that the DXF task was not cancelled after canceling the add index job [#issue](https://github.com/pingcap/tidb/issues/64129) @[tangenta](https://github.com/tangenta) + - Fix the issue that embedded ANALYZE might not be triggered for multiple schema changes [#65040](https://github.com/pingcap/tidb/issues/65040) @[joechenrh](https://github.com/joechenrh) + - Fix the issue that the DXF (Distributed eXecution Framework) task is not cancelled after canceling the `ADD INDEX` job [#issue](https://github.com/pingcap/tidb/issues/64129) @[tangenta](https://github.com/tangenta) - fix incorrect check to determing whether to load table info for tables contain foreign key [#issue](https://github.com/pingcap/tidb/issues/60444) @[JQWong7](https://github.com/JQWong7) - - fix incorrect auto ID setting after cross-database rename table [#issue](https://github.com/pingcap/tidb/issues/64561) @[joechenrh](https://github.com/joechenrh) - - fix incorrect handling meta key for older version of TiDB [#issue](https://github.com/pingcap/tidb/issues/64323) @[wjhuang2016](https://github.com/wjhuang2016) - - fix ligtning doesnt' report error for schema files without trailing semicolon [#issue](https://github.com/pingcap/tidb/issues/63414) @[GMHDBJD](https://github.com/GMHDBJD) - - fix the dead loop when reading files during IMPORT INTO global sort [#issue](https://github.com/pingcap/tidb/issues/61177) @[CbcWestwolf](https://github.com/CbcWestwolf) - - fix the panic when processing generated columns for IMPORT INTO [#issue](https://github.com/pingcap/tidb/issues/64657) @[D3Hunter](https://github.com/D3Hunter) - - 修复在一个语句中有多个 `AS OF TIMESTAMP` 表达式时可能误报错的问题 [#issue](https://github.com/pingcap/tidb/issues/65090) @[you06](https://github.com/you06) + - Fix the issue that the auto ID setting is incorrect after renaming a table cross databases [#issue](https://github.com/pingcap/tidb/issues/64561) @[joechenrh](https://github.com/joechenrh) + - Fix the high CPU usage issue caused by incorrect handling of meta keys [#issue](https://github.com/pingcap/tidb/issues/64323) @[wjhuang2016](https://github.com/wjhuang2016) + - Fix the issue that TiDB Ligtning does not report an error when a schema file lacks a trailing semicolon [#63414](https://github.com/pingcap/tidb/issues/63414) @[GMHDBJD](https://github.com/GMHDBJD) + - Fix the issue that an infinite loop occurs when reading files during an `IMPORT INTO` operation with Global Sort enabled [#61177](https://github.com/pingcap/tidb/issues/61177) @[CbcWestwolf](https://github.com/CbcWestwolf) + - Fix the panic issue when processing generated columns for `IMPORT INTO` [#issue](https://github.com/pingcap/tidb/issues/64657) @[D3Hunter](https://github.com/D3Hunter) + - Fix the issue that an error might be incorrectly reported when a single SQL statement contains multiple `AS OF TIMESTAMP` expressions [#65090](https://github.com/pingcap/tidb/issues/65090) @[you06](https://github.com/you06) - (dup): release-9.0.0.md > Bug fixes> TiDB - Fix the potential OOM issue when querying `information_schema.tables` by improving memory usage monitoring when quering system tables [#58985](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) + TiKV From 18936b8d334c86a266c6058367b78ef0ce2b10df Mon Sep 17 00:00:00 2001 From: xixirangrang Date: Thu, 8 Jan 2026 12:07:06 +0800 Subject: [PATCH 36/45] Apply suggestions from code review --- releases/release-8.5.5.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 3b31554459b78..79a09aea5d5aa 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -236,15 +236,15 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - 修复缓存表在走 TiFlash 副本读取时可能出现的 goroutine 和内存泄漏问题 [#63329](https://github.com/pingcap/tidb/issues/63329) @[xzhangxian1008](https://github.com/xzhangxian1008) - Fix the issue that foreign key is not updated after running `ALTER TABLE child CHANGE COLUMN` to modify a column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) - Fix the issue that an error occurs when decoding the `RENAME TABLE` job arg from an earlier version [#64413](https://github.com/pingcap/tidb/issues/64413) @[joechenrh](https://github.com/joechenrh) - - Fix missing rebase auto increment not executed if BR restore failed [#64761](https://github.com/pingcap/tidb/issues/64761) @[joechenrh](https://github.com/joechenrh) + - Fix the issue that the auto increment is not rebased if BR restore fails [#60804](https://github.com/pingcap/tidb/issues/60804) @[joechenrh](https://github.com/joechenrh) - Fix the OOM issue when querying `information_schema` tables [#58985](https://github.com/pingcap/tidb/issues/58985) @[tangenta](https://github.com/tangenta) - Fix the isse that the TiDB node might get stuck during upgrade [#64539](https://github.com/pingcap/tidb/issues/64539) @[joechenrh](https://github.com/joechenrh) - Fix the issue that admin check does not report errors when there are no index records [#63698](https://github.com/pingcap/tidb/issues/63698) @[wjhuang2016](https://github.com/wjhuang2016) - Fix the issue that data indexes are inconsistent when changing the collation with modify column [#61668](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) - - fix incorrect initialization for foreign key related fields when copying table info [#issue](https://github.com/pingcap/tidb/issues/61668) @[tangenta](https://github.com/tangenta) - Fix the issue that embedded ANALYZE might not be triggered for multiple schema changes [#65040](https://github.com/pingcap/tidb/issues/65040) @[joechenrh](https://github.com/joechenrh) - Fix the issue that the DXF (Distributed eXecution Framework) task is not cancelled after canceling the `ADD INDEX` job [#issue](https://github.com/pingcap/tidb/issues/64129) @[tangenta](https://github.com/tangenta) - - fix incorrect check to determing whether to load table info for tables contain foreign key [#issue](https://github.com/pingcap/tidb/issues/60444) @[JQWong7](https://github.com/JQWong7) + - Fix the issue that the check is incorrect when determining whether to load the table information for tables that contain foreign keys [#60044](https://github.com/pingcap/tidb/issues/60044) @[JQWong7](https://github.com/JQWong7) + - Fix the issue that initialization for foreign keys related fields is incorrect when copying the table information [#60044](https://github.com/pingcap/tidb/issues/60044) @[JQWong7](https://github.com/JQWong7) - Fix the issue that the auto ID setting is incorrect after renaming a table cross databases [#issue](https://github.com/pingcap/tidb/issues/64561) @[joechenrh](https://github.com/joechenrh) - Fix the high CPU usage issue caused by incorrect handling of meta keys [#issue](https://github.com/pingcap/tidb/issues/64323) @[wjhuang2016](https://github.com/wjhuang2016) - Fix the issue that TiDB Ligtning does not report an error when a schema file lacks a trailing semicolon [#63414](https://github.com/pingcap/tidb/issues/63414) @[GMHDBJD](https://github.com/GMHDBJD) From a451d7f0418bff07b4aba473983a08281d3762c6 Mon Sep 17 00:00:00 2001 From: xixirangrang Date: Thu, 8 Jan 2026 13:40:57 +0800 Subject: [PATCH 37/45] Apply suggestions from code review --- releases/release-8.5.5.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 79a09aea5d5aa..257823cfa6863 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -274,9 +274,9 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiFlash - - 修复在 BR restore 的过程中，TiFlash 可能 panic 的问题 [#10606](https://github.com/pingcap/tiflash/issues/10606) @[CalvinNeo](https://github.com/CalvinNeo) - - 修复在 BR restore 的过程中，TiFlash 不能充分利用超过 16 核 CPU 进行数据恢复的问题 [#10605](https://github.com/pingcap/tiflash/issues/10605) @[JaySon-Huang](https://github.com/JaySon-Huang) - - 修复 GROUP_CONCAT 触发落盘时可能导致 TiFlash 异常退出的问题 [#10553](https://github.com/pingcap/tiflash/issues/10553) @[ChangRui-Ryan](https://github.com/ChangRui-Ryan) + - Fix the issue that TiFlash might panic when BR is restoring data [#10606](https://github.com/pingcap/tiflash/issues/10606) @[CalvinNeo](https://github.com/CalvinNeo) + - Fix the issue that TiFlash cannot fully utilize more than 16 CPU cores when BR is restoring data [#10605](https://github.com/pingcap/tiflash/issues/10605) @[JaySon-Huang](https://github.com/JaySon-Huang) + - Fix the issue that TiFlash might exit unexpectedly when `GROUP_CONCAT` triggers a disk spill [#10553](https://github.com/pingcap/tiflash/issues/10553) @[ChangRui-Ryan](https://github.com/ChangRui-Ryan) + Tools From bcd1c1b998c41c905d0f79ea19aa705d15518d46 Mon Sep 17 00:00:00 2001 From: xixirangrang Date: Thu, 8 Jan 2026 14:30:08 +0800 Subject: [PATCH 38/45] Apply suggestions from code review --- releases/release-8.5.5.md | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 257823cfa6863..d536105511d1a 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -195,12 +195,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - 将 `tidb_analyze_column_options` 的默认值设置为 `all` [#64992](https://github.com/pingcap/tidb/issues/64992) @[0xPoe](https://github.com/0xPoe) - 优化 IndexHashJoin 的执行方式，在部分 JOIN 场景下采用增量处理以避免一次性加载大量数据，显著降低内存占用并提升执行性能 [#63303](https://github.com/pingcap/tidb/issues/63303) @[ChangRui-Ryan](https://github.com/ChangRui-Ryan) - (dup): release-9.0.0.md > Improvements> TiDB - Optimize the CPU usage of internal SQL statements in the Distributed eXecution Framework (DXF) [#59344](https://github.com/pingcap/tidb/issues/59344) @[D3Hunter](https://github.com/D3Hunter) + - Improve the performance of the expression.Contains function [#61373](https://github.com/pingcap/tidb/issues/61373) @[hawkingrei](https://github.com/hawkingrei) + TiKV - - Introduces CPU-aware scaling for the unified read pool to avoid CPU starvation under hot read workloads. [#18464](https://github.com/tikv/tikv/issues/18464) @[mittalrishabh](https://github.com/mittalrishabh) - - Adds network latency awareness to slow score to avoid scheduling leaders on TiKV nodes with unstable network conditions. [#18797](https://github.com/tikv/tikv/issues/18797) @[okJiang](https://github.com/okJiang) - - Optimizes hibernate behavior by allowing leaders to enter hibernation once a majority vote is reached, without waiting for down non-voter peers. [#19070](https://github.com/tikv/tikv/issues/19070) @[jiadebin](https://github.com/jiadebin) + - Introduce CPU-aware scaling for the unified read pool to avoid CPU starvation under hot read workloads [#18464](https://github.com/tikv/tikv/issues/18464) @[mittalrishabh](https://github.com/mittalrishabh) + - Add network latency awareness to slow score to avoid scheduling leaders on TiKV nodes with unstable network conditions [#18797](https://github.com/tikv/tikv/issues/18797) @[okJiang](https://github.com/okJiang) + - Optimize hibernate behavior by allowing leaders to enter hibernation once a majority vote is reached, without waiting for down non-voter peers [#19070](https://github.com/tikv/tikv/issues/19070) @[jiadebin](https://github.com/jiadebin) - (dup): release-9.0.0.md > Improvements> TiKV - Throttle BR log restore requests when TiKV memory usage is high to prevent TiKV OOM [#18124](https://github.com/tikv/tikv/issues/18124) @[3pointer](https://github.com/3pointer) + PD @@ -220,20 +221,19 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiDB - - 修复 TiDB 初始化时无法读取最新的 tidb_mem_quota_binding_cache 变量值初始化 binding 的问题 [#65381](https://github.com/pingcap/tidb/issues/65381) @[qw4990](https://github.com/qw4990) - - 修复了在 `extractBestCNFItemRanges` 中错误地跳过候选项导致查询范围计算不精确的问题 [#62547](https://github.com/pingcap/tidb/issues/62547) @[hawkingrei](https://github.com/hawkingrei) - - 修复了 `plan replayer` 无法加载 binding 的问题 [#64811](https://github.com/pingcap/tidb/issues/64811) @[hawkingrei](https://github.com/hawkingrei) - - 修复了 `PointGet` 在有足够内存时仍不复用 chunk 导致不必要内存分配的问题 [#63920](https://github.com/pingcap/tidb/issues/63920) @[hawkingrei](https://github.com/hawkingrei) - - 修复了 `LogicalProjection.DeriveStats` 分配过多内存的问题 [#63810](https://github.com/pingcap/tidb/issues/63810) @[hawkingrei](https://github.com/hawkingrei) - - 修复了当查询发生 panic 时 `plan replayer` 无法 dump 的问题 [#64835](https://github.com/pingcap/tidb/issues/64835) @[hawkingrei](https://github.com/hawkingrei) - - 提升了 `expression.Contains` 函数的性能 [#61373](https://github.com/pingcap/tidb/issues/61373) @[hawkingrei](https://github.com/hawkingrei) - - 修复当计划缓存开启时，关联子查询可能产生非预期的全表扫描的问题 [#64645](https://github.com/pingcap/tidb/issues/64645) @[winoros](https://github.com/winoros) - - 修复系统表会污染表健康度监控的问题 [#57176](https://github.com/pingcap/tidb/issues/57176), [#64080](https://github.com/pingcap/tidb/issues/64080) @[0xPoe](https://github.com/0xPoe) - - 修复 auto-anlyze 关闭之后 `mysql.tidb_ddl_notifier` 不能被清理的问题 [#64038](https://github.com/pingcap/tidb/issues/64038) @[0xPoe](https://github.com/0xPoe) - - 修复了在 `newLocalColumnPool` 中重复分配 column 的问题 [#63809](https://github.com/pingcap/tidb/issues/63809) @[hawkingrei](https://github.com/hawkingrei) - - 减少无效的 sync load 加载失败警告日志 [#63880](https://github.com/pingcap/tidb/issues/63880) @[0xPoe](https://github.com/0xPoe) - - 修复手动 kill 正在执行事务的 connection 可能导致 tidb 发生 panic 异常退出的问题 [#63956](https://github.com/pingcap/tidb/issues/63956) @[wshwsh12](https://github.com/wshwsh12) - - 修复缓存表在走 TiFlash 副本读取时可能出现的 goroutine 和内存泄漏问题 [#63329](https://github.com/pingcap/tidb/issues/63329) @[xzhangxian1008](https://github.com/xzhangxian1008) + - Fix the issue that TiDB fails to read the latest value of the tidb_mem_quota_binding_cache variable for initialization during the startup process [#65381](https://github.com/pingcap/tidb/issues/65381) @[qw4990](https://github.com/qw4990) + - Fix the issue that candidate items are incorrectly skipped in extractBestCNFItemRanges, leading to inaccurate query range calculation [#62547](https://github.com/pingcap/tidb/issues/62547) @[hawkingrei](https://github.com/hawkingrei) + - Fix the issue that `plan replayer` cannot load the binding [#64811](https://github.com/pingcap/tidb/issues/64811) @[hawkingrei](https://github.com/hawkingrei) + - Fix the issue that `PointGet` fails to reuse chunks even when memory is sufficient, leading to unnecessary memory allocations [#63920](https://github.com/pingcap/tidb/issues/63920) @[hawkingrei](https://github.com/hawkingrei) + - Fix the issue that `LogicalProjection.DeriveStats` consumes excessive memory during allocation [#63810](https://github.com/pingcap/tidb/issues/63810) @[hawkingrei](https://github.com/hawkingrei) + - Fix the issue that TiDB fails to dump the plan replayer when a query panics [#64835](https://github.com/pingcap/tidb/issues/64835) @[hawkingrei](https://github.com/hawkingrei) + - Fix the issue that correlated subqueries might trigger unexpected full table scans when the Plan Cache is enabled [#64645](https://github.com/pingcap/tidb/issues/64645) @[winoros](https://github.com/winoros) + - Fix the issue that system tables cause incorrect calculation of table health metrics [#57176](https://github.com/pingcap/tidb/issues/57176), [#64080](https://github.com/pingcap/tidb/issues/64080) @[0xPoe](https://github.com/0xPoe) + - Fix the issue that the `mysql.tidb_ddl_notifier` table cannot be cleaned up when automatic statistics updates are disabled (`tidb_enable_auto_analyze = OFF`) [#64038](https://github.com/pingcap/tidb/issues/64038) @[0xPoe](https://github.com/0xPoe) + - Fix the issue that columns are redundantly allocated in `newLocalColumnPool` [#63809](https://github.com/pingcap/tidb/issues/63809) @[hawkingrei](https://github.com/hawkingrei) + - Fix the issue that there are redundant `syncload` failure warning logs [#63880](https://github.com/pingcap/tidb/issues/63880) @[0xPoe](https://github.com/0xPoe) + - Fix the issue that TiDB might panic and exit unexpectedly when a connection that runs an active transaction is manually terminated [#63956](https://github.com/pingcap/tidb/issues/63956) @[wshwsh12](https://github.com/wshwsh12) + - Fix the issue that goroutine and memory leaks might occur when a cached table reads from a TiFlash replica [#63329](https://github.com/pingcap/tidb/issues/63329) @[xzhangxian1008](https://github.com/xzhangxian1008) - Fix the issue that foreign key is not updated after running `ALTER TABLE child CHANGE COLUMN` to modify a column [#issue](https://github.com/pingcap/tidb/issues/59705) @[fzzf678](https://github.com/fzzf678) - Fix the issue that an error occurs when decoding the `RENAME TABLE` job arg from an earlier version [#64413](https://github.com/pingcap/tidb/issues/64413) @[joechenrh](https://github.com/joechenrh) - Fix the issue that the auto increment is not rebased if BR restore fails [#60804](https://github.com/pingcap/tidb/issues/60804) @[joechenrh](https://github.com/joechenrh) From d33be468727f3bc86450e7e4c3e3675d43801e0f Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Thu, 8 Jan 2026 18:17:13 +0800 Subject: [PATCH 39/45] update the compatibility info --- releases/release-8.5.5.md | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index d536105511d1a..8faaa12b9bf7f 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -157,7 +157,6 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### Behavior changes -* When using [`IMPORT INTO`](/sql-statements/sql-statement-import-into.md) with [Global Sort](/tidb-global-sort.md) enabled, primary key or unique index conflicts are now automatically resolved by removing all conflicting rows (none of the conflicting rows are preserved), instead of causing the task to fail. The number of conflicted rows appears in the `Result_Message` column of `SHOW IMPORT JOBS` output, and detailed conflict information is stored in cloud storage. For more information, see [`IMPORT INTO` conflict resolution](/sql-statements/sql-statement-import-into.md#conflict-resolution). ### MySQL compatibility @@ -175,7 +174,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- | -------- | -------- | -------- | -------- | | PD | [`schedule.max-affinity-merge-region-size`](https://docs.pingcap.com/tidb/v8.5/pd-configuration-file#max-affinity-merge-region-size-new-in-v855) | Newly added | Controls the threshold for automatically merging adjacent small Regions within the same [affinity group](https://docs.pingcap.com/tidb/v8.5/table-affinity). The default value is `256`, in MiB. | | PD | [`schedule.affinity-schedule-limit`](https://docs.pingcap.com/tidb/v8.5/pd-configuration-file#affinity-schedule-limit-new-in-v855) | Newly added | Controls the number of [affinity](https://docs.pingcap.com/tidb/v8.5/table-affinity) scheduling tasks that can be performed concurrently. The default value is `0`, which means that affinity scheduling is disabled by default. | -| TiKV | [`performance.enable-async-batch-get`](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#enable-async-batch-get-new-in-v855) | Newly added | Controls whether TiDB uses asynchronous mode to execute the Batch Get operator. The default value is `true`. | +| TiDB | [`performance.enable-async-batch-get`](https://docs.pingcap.com/tidb/v8.5/tidb-configuration-file#enable-async-batch-get-new-in-v855) | Newly added | Controls whether TiDB uses asynchronous mode to execute the Batch Get operator. The default value is `true`. | | TiKV | [`server.graceful-shutdown-timeout`](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-new-in-v855) | Newly added | Controls the timeout duration for graceful shutdown of TiKV. The default value is `20s`. | | TiKV | [`server.inspect-network-interval`](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#inspect-network-interval-new-in-v855) | Newly added | Controls the interval at which the TiKV HealthChecker actively performs network detection to PD and other TiKV nodes. The default value is `100ms`. | | BR | [`--checkpoint-storage`](/br/br-checkpoint-restore.md#implementation-details-store-checkpoint-data-in-the-downstream-cluster) | Newly added | Specifies an external storage for checkpoint data. | From 3a92864465f929e7b46df0d0c4fa85540586063c Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Thu, 8 Jan 2026 18:17:46 +0800 Subject: [PATCH 40/45] translate TiDB improvements and PD bug fixes --- releases/release-8.5.5.md | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 8faaa12b9bf7f..a0e3bed582da3 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -189,10 +189,10 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiDB - - improve the error message for import into when there are encoding errors [#63763](https://github.com/pingcap/tidb/issues/63763) @[D3Hunter](https://github.com/D3Hunter) - - change the parser for parquet format to get better performance [#62906](https://github.com/pingcap/tidb/issues/) @[joechenrh](https://github.com/joechenrh) - - 将 `tidb_analyze_column_options` 的默认值设置为 `all` [#64992](https://github.com/pingcap/tidb/issues/64992) @[0xPoe](https://github.com/0xPoe) - - 优化 IndexHashJoin 的执行方式，在部分 JOIN 场景下采用增量处理以避免一次性加载大量数据，显著降低内存占用并提升执行性能 [#63303](https://github.com/pingcap/tidb/issues/63303) @[ChangRui-Ryan](https://github.com/ChangRui-Ryan) + - Improve error messages for `IMPORT INTO` when encoding errors occur to help users identify issues more accurately [#63763](https://github.com/pingcap/tidb/issues/63763) @[D3Hunter](https://github.com/D3Hunter) + - Enhance the parsing mechanism for Parquet files to improve the import performance of Parquet-formatted data [#62906](https://github.com/pingcap/tidb/issues/62906) @[joechenrh](https://github.com/joechenrh) + - Set the default value of `tidb_analyze_column_options` to `all` to collect statistics for all columns by default [#64992](https://github.com/pingcap/tidb/issues/64992) @[0xPoe](https://github.com/0xPoe) + - Optimize the execution logic of the `IndexHashJoin` operator by using incremental processing in specific JOIN scenarios to avoid loading large amounts of data at once, significantly reducing memory usage and improving performance [#63303](https://github.com/pingcap/tidb/issues/63303) @[ChangRui-Ryan](https://github.com/ChangRui-Ryan) - (dup): release-9.0.0.md > Improvements> TiDB - Optimize the CPU usage of internal SQL statements in the Distributed eXecution Framework (DXF) [#59344](https://github.com/pingcap/tidb/issues/59344) @[D3Hunter](https://github.com/D3Hunter) - Improve the performance of the expression.Contains function [#61373](https://github.com/pingcap/tidb/issues/61373) @[hawkingrei](https://github.com/hawkingrei) @@ -263,13 +263,13 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + PD - - 修复节点在上线过程中可能无法下线的问题 [#8997](https://github.com/tikv/pd/issues/8997) @[lhy1024](https://github.com/lhy1024) - - 修复因大量 leader transfer 可能导致 region size 跳变的问题 [#10014](https://github.com/tikv/pd/issues/10014) @[lhy1024](https://github.com/lhy1024) - - 修复调度过程中可能导致 PD panic 的问题 [#9951](https://github.com/tikv/pd/issues/9951) @[bufferflies](https://github.com/bufferflies) - - 修复导入过程中数据不均衡的问题 [#9088](https://github.com/tikv/pd/issues/9088) @[GMHDBJD](https://github.com/GMHDBJD) - - 修复开启 PD follower handle 后遇到错误时，无法将请求回退到 leader 处理的问题 [#64933](https://github.com/pingcap/tidb/issues/64933) @[okJiang](https://github.com/okJiang) - - 修复微服务请求没有正常转发的问题 [#9825](https://github.com/tikv/pd/issues/9825) @[lhy1024](https://github.com/lhy1024) [#9825](https://github.com/tikv/pd/issues/9825) @[lhy1024](https://github.com/lhy1024) - - 修复微服务 TLS 配置问题 [#9367](https://github.com/tikv/pd/issues/9367) @[rleungx](https://github.com/rleungx) + - Fix the issue that a node might not be removable during the process of bringing it online [#8997](https://github.com/tikv/pd/issues/8997) @[lhy1024](https://github.com/lhy1024) + - Fix the issue that a large number of Leader transfers might cause sudden changes in Region size [#10014](https://github.com/tikv/pd/issues/10014) @[lhy1024](https://github.com/lhy1024) + - Fix the issue that might cause PD panic during scheduling [#9951](https://github.com/tikv/pd/issues/9951) @[bufferflies](https://github.com/bufferflies) + - Fix the issue that data might become imbalanced during the import process [#9088](https://github.com/tikv/pd/issues/9088) @[GMHDBJD](https://github.com/GMHDBJD) + - Fix the issue that, after enabling the Active PD Follower feature, requests that fail on a Follower node cannot correctly fall back to the Leader node for retry [#64933](https://github.com/pingcap/tidb/issues/64933) @[okJiang](https://github.com/okJiang) + - Fix the issue that some requests are not correctly forwarded in PD microservices mode [#9825](https://github.com/tikv/pd/issues/9825) @[lhy1024](https://github.com/lhy1024) + - Fix the issue that connections might fail due to incorrect TLS configuration loading in the `tso` and `scheduling` microservices [#9367](https://github.com/tikv/pd/issues/9367) @[rleungx](https://github.com/rleungx) + TiFlash From d86c38bd0de9e453140b5b83a5409f1fd5a828ab Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Fri, 9 Jan 2026 13:34:38 +0800 Subject: [PATCH 41/45] translate TiCDC improvements and bug fixes --- releases/release-8.5.5.md | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index a0e3bed582da3..7f0df86f2c556 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -214,7 +214,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiCDC - - Add more verification for the changefeed config when creating changefeed. [#12253](https://github.com/pingcap/tiflow/issues/12253) @[wk989898](https://github.com/wk989898) + - Enhance the configuration validation logic for changefeeds: when creating or updating a changefeed, if a column referenced in the Dispatcher configuration does not exist, TiCDC returns an error and rejects the operation to prevent execution failures [#12253](https://github.com/pingcap/tiflow/issues/12253) @[wk989898](https://github.com/wk989898) ## Bug fixes @@ -291,9 +291,9 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiCDC - - Fix the issue that may cause DML loss while failing to close the writer of the storage sink [#12436](https://github.com/pingcap/tiflow/issues/12436) @[wk989898](https://github.com/wk989898) - - Fix the issue that causes the changefeed to fail when truncating partition tables [#12430](https://github.com/pingcap/tiflow/issues/12430) @[wk989898](https://github.com/wk989898) - - Fix the incorrect execution order of split DDLs generated from a multi-table DDL statement [#12449](https://github.com/pingcap/tiflow/issues/12449) @[wlwilliamx](https://github.com/wlwilliamx) - - Upgrade aws-sdk-go-v2 dependency to fix glue schema registry[#12424](https://github.com/pingcap/tiflow/issues/12424) @[wk989898](https://github.com/wk989898) - - Fix the issue that may cause the sink memory quota not to be released [#18169](https://github.com/tikv/tikv/issues/18169) @[asddongmen](https://github.com/asddongmen) - - Fix the issue that may cause the sink memory quota not to be released [#18915](https://github.com/tikv/tikv/issues/18915) @[asddongmen](https://github.com/asddongmen) + - Fix the issue that data might be lost during replication to object storage because Writer close errors are not correctly captured [#12436](https://github.com/pingcap/tiflow/issues/12436) @[wk989898](https://github.com/wk989898) + - Fix the issue that replicating a `TRUNCATE` operation on a partitioned table might cause changefeed failures [#12430](https://github.com/pingcap/tiflow/issues/12430) @[wk989898](https://github.com/wk989898) + - Fix the issue that downstream execution order might be incorrect when replicating multi-table `RENAME` DDL statements [#12449](https://github.com/pingcap/tiflow/issues/12449) @[wlwilliamx](https://github.com/wlwilliamx) + - Fix the connection errors that might occur when using Glue Schema Registry by upgrading the `aws-sdk-go-v2` dependency version [#12424](https://github.com/pingcap/tiflow/issues/12424) @[wk989898](https://github.com/wk989898) + - Fix the issue that changefeed tasks might get stuck because the TiKV CDC component fails to release memory quotas correctly after a restart [#18169](https://github.com/tikv/tikv/issues/18169) @[asddongmen](https://github.com/asddongmen) + - Fix the issue that gRPC connections might be unexpectedly closed due to being misjudged as idle when incremental scan tasks accumulate in TiKV CDC [#18915](https://github.com/tikv/tikv/issues/18915) @[asddongmen](https://github.com/asddongmen) From 28402abf17ce3e10767d89b061a812d2f374a846 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Fri, 9 Jan 2026 13:38:16 +0800 Subject: [PATCH 42/45] Apply suggestions from code review --- releases/release-8.5.5.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 7f0df86f2c556..7465ac1ddc421 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -93,7 +93,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- ### SQL -* Support dynamically modifying the concurrency and throughput of distributed `ADD INDEX` jobs [#62120](https://github.com/pingcap/tidb/pull/62120) @[joechenrh](https://github.com/joechenrh) **tw@qiancai** +* Support dynamically modifying the concurrency and throughput of distributed `ADD INDEX` jobs [#64947](https://github.com/pingcap/tidb/issues/64947) @[joechenrh](https://github.com/joechenrh) **tw@qiancai** In TiDB versions earlier than v8.5.5, when the Distributed eXecution Framework (DXF) [`tidb_enable_dist_task`](/system-variables/#tidb_enable_dist_task-new-in-v710) is enabled, modifying the `THREAD`, `BATCH_SIZE`, or `MAX_WRITE_SPEED` parameters of a running `ADD INDEX` job is not supported. To change these parameters, you have to cancel the running `ADD INDEX` job, reconfigure the parameters, and then resubmit the job, which is inefficient. From e2dbfbc227b958b6a007823c0c266a932acdd5e4 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Fri, 9 Jan 2026 15:51:56 +0800 Subject: [PATCH 43/45] add the default value of tidb_analyze_column_options --- releases/release-8.5.5.md | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 7465ac1ddc421..2fd1c01a33ff2 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -53,7 +53,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Support table-level data affinity to improve query performance (experimental) [#9764](https://github.com/tikv/pd/issues/9764) @[lhy1024](https://github.com/lhy1024) **tw@qiancai** - Starting from v8.5.5, you can set the `AFFINITY` table option to `table` or `partition` when creating or altering a table. When this option is enabled, PD groups Regions that belong to the same table or the same partition into a single affinity group. During scheduling, PD preferentially places the Leaders and Voter replicas of these Regions on the same small set of TiKV nodes. In this scenario, by using the [`INDEX_LOOKUP_PUSHDOWN`](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855) hint in queries, you can explicitly instruct the optimizer to push index lookups down to TiKV, reducing the latency caused by cross-node scattered queries and improving query performance. + Starting from v8.5.5, you can set the `AFFINITY` table option to `table` or `partition` when creating or altering a table. When this option is enabled, PD groups Regions that belong to the same table or the same partition into a single affinity group. During scheduling, PD prioritizes placing the Leaders and Voter replicas of these Regions on the same subset of a few TiKV nodes. In this scenario, by using the [`INDEX_LOOKUP_PUSHDOWN`](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855) hint in queries, you can explicitly instruct the optimizer to push index lookups down to TiKV, reducing the latency caused by cross-node scattered queries and improving query performance. Note that this feature is currently experimental and is disabled by default. To enable it, set the PD configuration item [`schedule.affinity-schedule-limit`](https://docs.pingcap.com/tidb/v8.5/pd-configuration-file#affinity-schedule-limit-new-in-v855) to a value greater than `0`. This configuration item controls the maximum number of affinity scheduling tasks that PD can perform concurrently. @@ -164,6 +164,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- | Variable name | Change type | Description | |--------|------------------------------|------| +| [`tidb_analyze_column_options`](/system-variables.md#tidb_analyze_column_options-new-in-v830) | Modified | Changes the default value from `PREDICATE` to `ALL` to improve the completeness of statistics. | | [`tidb_advancer_check_point_lag_limit`](https://docs.pingcap.com/tidb/v8.5/system-variables#tidb_advancer_check_point_lag_limit-new-in-v855) | Newly added | Controls the maximum allowed checkpoint lag for a log backup task. The default value is `48h0m0s`. If a task's checkpoint lag exceeds this limit, TiDB Advancer pauses the task. | | [`tidb_cb_pd_metadata_error_rate_threshold_ratio`](https://docs.pingcap.com/tidb/v8.5/system-variables#tidb_cb_pd_metadata_error_rate_threshold_ratio-new-in-v855) | Newly added | Controls when TiDB triggers the circuit breaker. The default value is `0`, which means the circuit breaker is disabled. Setting a value between `0.01` and `1` enables it, causing the circuit breaker to trigger when the error rate of specific requests sent to PD reaches or exceeds the threshold. | | [`tidb_index_lookup_pushdown_policy`](https://docs.pingcap.com/tidb/v8.5/system-variables#tidb_index_lookup_pushdown_policy-new-in-v855) | Newly added | Controls whether and when TiDB pushes the `IndexLookUp` operator down to TiKV. The default value is `hint-only`, which means TiDB pushes the `IndexLookUp` operator down to TiKV only when the [`INDEX_LOOKUP_PUSHDOWN`](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855) hint is explicitly specified in the SQL statement. | From a4af9887abc92dce31ce11deebdc8ea3f5807ffa Mon Sep 17 00:00:00 2001 From: Aolin Date: Fri, 9 Jan 2026 16:03:32 +0800 Subject: [PATCH 44/45] Apply suggestions from code review Co-authored-by: Grace Cai --- releases/release-8.5.5.md | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 2fd1c01a33ff2..9e5da25c9c02b 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -43,9 +43,9 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Support pushing index lookups down to TiKV to improve query performance [#62575](https://github.com/pingcap/tidb/issues/62575) @[lcwangchao](https://github.com/lcwangchao) - Starting from v8.5.5, TiDB supports using optimizer hints to push the `IndexLookUp` operator down to TiKV nodes. This reduces the number of remote procedure calls (RPCs) and can improve query performance. The actual performance improvement varies depending on the specific workload and requires testing for verification. + Starting from v8.5.5, TiDB supports using [optimizer hints](/optimizer-hints.md) to push the `IndexLookUp` operator down to TiKV nodes. This reduces the number of remote procedure calls (RPCs) and can improve query performance. The actual performance improvement varies depending on the specific workload and requires testing for verification. - You can use the [`INDEX_LOOKUP_PUSHDOWN(t1_name, idx1_name [, idx2_name ...])`](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855) hint to explicitly instruct the optimizer to push index lookups down to TiKV for a specific table. It is recommended to combine this hint with the table's AFFINITY attribute. For example, set `AFFINITY="table"` for regular tables and `AFFINITY="partition"` for partitioned tables. + To explicitly instruct the optimizer to push index lookups down to TiKV for a specific table, you can use the [`INDEX_LOOKUP_PUSHDOWN(t1_name, idx1_name [, idx2_name ...])`](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#index_lookup_pushdownt1_name-idx1_name--idx2_name--new-in-v855) hint. It is recommended to combine this hint with the table's AFFINITY attribute. For example, set `AFFINITY="table"` for regular tables and `AFFINITY="partition"` for partitioned tables. To disable index lookup pushdown to TiKV for a specific table, use the [`NO_INDEX_LOOKUP_PUSHDOWN(t1_name)`](https://docs.pingcap.com/tidb/v8.5/optimizer-hints#no_index_lookup_pushdownt1_name--new-in-v855) hint. @@ -125,7 +125,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- * Add storage engine identifiers to statement summary tables and slow query logs [#61736](https://github.com/pingcap/tidb/issues/61736) @[henrybw](https://github.com/henrybw) **tw@Oreoxmt** - When both TiKV and TiFlash are deployed in a cluster, users often need to filter SQL statements by storage engine during database diagnostics and performance optimization. For example, if TiFlash is under high load, users might need to identify SQL statements running on TiFlash to locate potential causes. To meet this need, starting from v9.0.0, TiDB adds storage engine identifier fields to statement summary tables and slow query logs. + When both TiKV and TiFlash are deployed in a cluster, users often need to filter SQL statements by storage engine during database diagnostics and performance optimization. For example, if TiFlash is under high load, users might need to identify SQL statements running on TiFlash to locate potential causes. To meet this need, starting from v8.5.5, TiDB adds storage engine identifier fields to statement summary tables and slow query logs. New fields in [statement summary tables](/statement-summary-tables.md): @@ -256,7 +256,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- + TiKV - Fix the issue that the `KV Cursor Operations` metric for analyze requests is always `0` [#19206](https://github.com/tikv/tikv/issues/19206) @[glorv](https://github.com/glorv) - - Fix the issue that PD heartbeats might report incorrect Region size or key statistics after a leader change [#19180](https://github.com/tikv/tikv/issues/19180) @[glorv](https://github.com/glorv) + - Fix the issue that Region heartbeats might report incorrect Region size or key statistics to PD after a leader change [#19180](https://github.com/tikv/tikv/issues/19180) @[glorv](https://github.com/glorv) - Fix the issue that unsafe recovery gets stuck by removing tombstone TiFlash learners from the unsafe recovery demotion list [#18458](https://github.com/tikv/tikv/issues/18458) @[v01dstar](https://github.com/v01dstar) - Fix the issue that snapshots might be canceled indefinitely during continuous writes, which blocks replica recovery [#18872](https://github.com/tikv/tikv/issues/18872) @[exit-code-1](https://github.com/exit-code-1) - Fix the issue that compaction slows down due to increased flow-control thresholds [#18708](https://github.com/tikv/tikv/issues/18708) @[hhwyt](https://github.com/hhwyt) @@ -287,7 +287,6 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- - Fix the issue that foreign keys cannot be properly restored during `restore point` [#61642](https://github.com/pingcap/tidb/issues/61642) @[Leavrth](https://github.com/Leavrth) - Fix the issue that restore fails if system table collations are incompatible between the backup and target cluster by adding the `--sys-check-collation` parameter to support restoring privilege tables from v6.5 to v7.5 [#64667](https://github.com/pingcap/tidb/issues/64667) @[Leavrth](https://github.com/Leavrth) - Fix the issue that `restore log` cannot be performed after a failed `restore point`, even when the operation is safe [#64908](https://github.com/pingcap/tidb/issues/64908) @[RidRisR](https://github.com/RidRisR) - - Fix the issue that Azure Managed Identity is unavailable [#19006](https://github.com/tikv/tikv/issues/19006) @[RidRisR](https://github.com/RidRisR) - Fix the issue that `restore point` from a checkpoint might panic when log backup data is mixed with a full backup [#58685](https://github.com/pingcap/tidb/issues/58685) @[YuJuncen](https://github.com/YuJuncen) + TiCDC From 7f1703a36cb06353256ebb7f7f3e9a6b0d9b5ec9 Mon Sep 17 00:00:00 2001 From: Grace Cai Date: Sat, 10 Jan 2026 11:34:28 +0800 Subject: [PATCH 45/45] add readpool.cpu-threshold --- releases/release-8.5.5.md | 1 + 1 file changed, 1 insertion(+) diff --git a/releases/release-8.5.5.md b/releases/release-8.5.5.md index 9e5da25c9c02b..f6c60f1dbeb91 100644 --- a/releases/release-8.5.5.md +++ b/releases/release-8.5.5.md @@ -176,6 +176,7 @@ Quick access: [Quick start](https://docs.pingcap.com/tidb/v8.5/quick-start-with- | PD | [`schedule.max-affinity-merge-region-size`](https://docs.pingcap.com/tidb/v8.5/pd-configuration-file#max-affinity-merge-region-size-new-in-v855) | Newly added | Controls the threshold for automatically merging adjacent small Regions within the same [affinity group](https://docs.pingcap.com/tidb/v8.5/table-affinity). The default value is `256`, in MiB. | | PD | [`schedule.affinity-schedule-limit`](https://docs.pingcap.com/tidb/v8.5/pd-configuration-file#affinity-schedule-limit-new-in-v855) | Newly added | Controls the number of [affinity](https://docs.pingcap.com/tidb/v8.5/table-affinity) scheduling tasks that can be performed concurrently. The default value is `0`, which means that affinity scheduling is disabled by default. | | TiDB | [`performance.enable-async-batch-get`](https://docs.pingcap.com/tidb/v8.5/tidb-configuration-file#enable-async-batch-get-new-in-v855) | Newly added | Controls whether TiDB uses asynchronous mode to execute the Batch Get operator. The default value is `true`. | +| TiKV | [`readpool.cpu-threshold`](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#cpu-threshold-new-in-v855) | Newly added | Specifies the CPU utilization threshold for the unified read pool. The default value is `0.0`, which means that there is no limit on the CPU usage of the unified read pool. The size of the thread pool is determined solely by the busy thread scaling algorithm, which adjusts the size dynamically based on the number of threads handling current tasks. | | TiKV | [`server.graceful-shutdown-timeout`](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#graceful-shutdown-timeout-new-in-v855) | Newly added | Controls the timeout duration for graceful shutdown of TiKV. The default value is `20s`. | | TiKV | [`server.inspect-network-interval`](https://docs.pingcap.com/tidb/v8.5/tikv-configuration-file#inspect-network-interval-new-in-v855) | Newly added | Controls the interval at which the TiKV HealthChecker actively performs network detection to PD and other TiKV nodes. The default value is `100ms`. | | BR | [`--checkpoint-storage`](/br/br-checkpoint-restore.md#implementation-details-store-checkpoint-data-in-the-downstream-cluster) | Newly added | Specifies an external storage for checkpoint data. |