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Speed up column permissions query. #94

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Merged
tuhaihe merged 1 commit into from
Apr 28, 2026
Merged

Speed up column permissions query. #94

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13 changes: 8 additions & 5 deletions backup/queries_table_defs.go
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Original file line number Diff line number Diff line change
Expand Up @@ -327,9 +327,9 @@ func GetColumnDefinitions(connectionPool *dbconn.DBConn) map[uint32][]ColumnDefi
ORDER BY a.attrelid, a.attnum`, relationAndSchemaFilterClause())

// In GPDB7+ we do not want to exclude child partitions, they function as separate tables.
// Cannot use unnest() in CASE statements anymore in GPDB 7+ so convert
// it to a LEFT JOIN LATERAL. We do not use LEFT JOIN LATERAL for GPDB 6
// because the CASE unnest() logic is more performant.
// Use a top-level unnest(CASE ...) AS privileges instead of LEFT JOIN LATERAL.
// This removes an extra join and per-array expansion, reducing planner/executor work
// when scanning large catalogs. Keep the GPDB6 CASE-unnest because it was faster there.
atLeast7Query := fmt.Sprintf(`
SELECT a.attrelid,
a.attnum,
Expand All @@ -343,7 +343,11 @@ func GetColumnDefinitions(connectionPool *dbconn.DBConn) map[uint32][]ColumnDefi
coalesce('('||pg_catalog.pg_get_expr(ad.adbin, ad.adrelid)||')', '') AS defaultval,
coalesce(d.description, '') AS comment,
a.attgenerated,
ljl_unnest AS privileges,
unnest(CASE
WHEN a.attacl IS NULL OR array_length(a.attacl, 1) IS NULL
THEN ARRAY[NULL::aclitem]
ELSE a.attacl
END) AS privileges,
CASE
WHEN a.attacl IS NULL THEN ''
WHEN array_upper(a.attacl, 1) = 0 THEN 'Empty'
Expand All @@ -365,7 +369,6 @@ func GetColumnDefinitions(connectionPool *dbconn.DBConn) map[uint32][]ColumnDefi
LEFT JOIN pg_collation coll ON a.attcollation = coll.oid
LEFT JOIN pg_namespace cn ON coll.collnamespace = cn.oid
LEFT JOIN pg_seclabel sec ON sec.objoid = a.attrelid AND sec.classoid = 'pg_class'::regclass AND sec.objsubid = a.attnum
LEFT JOIN LATERAL unnest(a.attacl) ljl_unnest ON a.attacl IS NOT NULL AND array_length(a.attacl, 1) != 0
WHERE %s
AND c.reltype <> 0
AND a.attnum > 0::pg_catalog.int2
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