Implement table & tree disk usage statistics

[shuwenwei]

Description

This PR implements disk-usage statistics collection in table level and device level for tree model. It adds the necessary data structures, background tasks, and read APIs to compute and expose disk usage metrics used by monitoring, admission control and operational tooling.

Tree Model (No Cache)

IoTDB> show disk_usage from root.test.**
+---------+----------+--------+-------------+-----------+
| Database|DataNodeId|RegionId|TimePartition|SizeInBytes|
+---------+----------+--------+-------------+-----------+
|root.test|         1|       3|            0|         70|
+---------+----------+--------+-------------+-----------+
Total line number = 1
It costs 0.959s

Implements ShowDiskUsageNode and ShowDiskUsageOperator.
• Disk usage is calculated by scanning relevant TsFiles at query time.
• Supports:
• Path pattern matching
• Time partition filtering
• Existing SQL semantics (SHOW DISK_USAGE)

Table Model (With Cache)

IoTDB:information_schema> select * from table_disk_usage
+--------+----------+-------+---------+--------------+-------------+
|database|table_name|datanode_id|region_id|time_partition|size_in_bytes|
+--------+----------+-------+---------+--------------+-------------+
|   test1|        t1|          1|        5|             0|          142|
|   test1|        t2|          1|        5|             0|            0|
|   test1|        t1|          1|        6|             0|            0|
|   test1|        t2|          1|        6|             0|           82|
+--------+----------+-------+---------+--------------+-------------+
Total line number = 4
It costs 2.821s

Table Model introduces a dedicated disk usage cache:
• TableDiskUsageCache manages all cache operations.
• A single-threaded background worker processes write, read, and maintenance tasks via an operation queue.
• Cache state is persistent across restarts.

Cached Data
• TsFile-level table size statistics
• Object file size deltas, recorded incrementally
• Periodic snapshot + delta compaction

Query Integration
• Exposes statistics via information_schema.table_disk_usage.
• Supports:
• Predicate pushdown (except on aggregated size columns)
• Limit / offset
• Parallel region-level scanning

[Copilot]

Pull request overview

This PR implements comprehensive disk usage statistics collection for both Tree Model (device-based) and Table Model databases in IoTDB. The implementation provides monitoring capabilities at the table/device level and time partition level.

Changes:

• Adds SHOW DISK_USAGE SQL statement for Tree Model with on-demand calculation
• Implements table_disk_usage information schema table for Table Model with persistent cache
• Introduces background task infrastructure for cache maintenance with periodic compaction
• Adds predicate push-down and limit/offset optimization support for information schema tables

Reviewed changes

Copilot reviewed 95 out of 95 changed files in this pull request and generated 33 comments.

Show a summary per file

File	Description
pom.xml	Updates tsfile version to 2.2.1-260205-SNAPSHOT
TsFileID.java	Adds SHALLOW_SIZE constant (contains bug)
InformationSchema.java	Adds table_disk_usage schema and push-down support (contains bug)
TableDiskUsageCache*.java	Core cache implementation with writer/reader classes
ShowDiskUsageNode.java	Plan node for tree model disk usage queries
TableDiskUsageInformationSchemaTableScanNode.java	Plan node for table model information schema scans
ShowDiskUsageOperator.java	Execution operator for tree model
DiskUsageStatisticUtil.java	Base utility class for disk usage calculation
IoTDBDescriptor.java	Configuration support (contains bug)
Integration tests	Comprehensive tests for both tree and table models

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

The method supportsPushDownLimitOffset checks if a key exists in columnsThatSupportPushDownPredicate instead of checking tablesThatSupportPushDownLimitOffset. This will cause incorrect behavior for tables that support limit/offset push-down but are not in the predicate push-down map. The condition should be tablesThatSupportPushDownLimitOffset.contains(tableName).

[Copilot]

Configuration property mismatch: The method sets maxRowsInCteBuffer instead of maxSubTaskNumForInformationTableScan. This will cause the wrong configuration property to be updated when loading hot-modified properties for max_sub_task_num_for_information_table_scan. The correct call should be conf.setMaxSubTaskNumForInformationTableScan(maxSubTaskNumForInformationTableScan).

Suggested change

	conf.setMaxRowsInCteBuffer(maxSubTaskNumForInformationTableScan);
	conf.setMaxSubTaskNumForInformationTableScan(maxSubTaskNumForInformationTableScan);

[Copilot]

Typo in comment: "af" should be "at". The comment should read "tsFileIDOffsetInValueFileMap should be null at first".

[Copilot]

Circular reference detected: TsFileID.SHALLOW_SIZE is defined as TsFileID.SHALLOW_SIZE. This will result in uninitialized constant value (likely 0) and incorrect memory estimation. The field should reference RamUsageEstimator.shallowSizeOfInstance(TsFileID.class) instead.

[Copilot]

The contents of this container are never accessed.

[Copilot]

This method overrides AbstractCompactionTest.tearDown; it is advisable to add an Override annotation.

[Copilot]

This method overrides AbstractCompactionTest.setUp; it is advisable to add an Override annotation.

[Copilot]

This method overrides AbstractCompactionTest.tearDown; it is advisable to add an Override annotation.

[Copilot]

This method overrides AbstractCompactionTest.setUp; it is advisable to add an Override annotation.

[Copilot]

This method overrides AutoCloseable.close; it is advisable to add an Override annotation.

[sonarqubecloud]

Quality Gate failed

Failed conditions
C Reliability Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

Catch issues before they fail your Quality Gate with our IDE extension SonarQube for IDE