From bd48ef6db6c83739ff5949d0945982ec9e6a90b8 Mon Sep 17 00:00:00 2001 From: Mikhail Nikalayeu Date: Sun, 25 Jan 2026 18:21:26 +0100 Subject: [PATCH v1 2/2] Add syscache for pg_inherits lookups MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 90eae926a introduced calls to get_partition_ancestors() in ExecInitPartitionInfo() to handle ON CONFLICT with REINDEX CONCURRENTLY on partitioned tables. That commit noted that get_partition_ancestors() is slow because it scans pg_inherits each time, and suggested adding a syscache. This commit implements that suggestion by adding a new syscache INHRELIDSEQNO on the pg_inherits_relid_seqno_index. The get_partition_parent_worker() function now uses SearchSysCache2() instead of a direct catalog scan, which benefits both get_partition_parent() and get_partition_ancestors(). Author: Mihail Nikalayeu Reviewed-by: Álvaro Herrera Discussion: https://postgr.es/m/202512021255.r3ouzsfyxg5r%40alvherre.pgsql --- src/backend/catalog/partition.c | 49 +++++++--------------------- src/backend/executor/execPartition.c | 3 -- src/include/catalog/pg_inherits.h | 1 + 3 files changed, 13 insertions(+), 40 deletions(-) diff --git a/src/backend/catalog/partition.c b/src/backend/catalog/partition.c index 28f3cade6ff..9b2528b9e8a 100644 --- a/src/backend/catalog/partition.c +++ b/src/backend/catalog/partition.c @@ -31,10 +31,8 @@ #include "utils/rel.h" #include "utils/syscache.h" -static Oid get_partition_parent_worker(Relation inhRel, Oid relid, - bool *detach_pending); -static void get_partition_ancestors_worker(Relation inhRel, Oid relid, - List **ancestors); +static Oid get_partition_parent_worker(Oid relid, bool *detach_pending); +static void get_partition_ancestors_worker(Oid relid, List **ancestors); /* * get_partition_parent @@ -52,14 +50,10 @@ static void get_partition_ancestors_worker(Relation inhRel, Oid relid, Oid get_partition_parent(Oid relid, bool even_if_detached) { - Relation catalogRelation; Oid result; bool detach_pending; - catalogRelation = table_open(InheritsRelationId, AccessShareLock); - - result = get_partition_parent_worker(catalogRelation, relid, - &detach_pending); + result = get_partition_parent_worker(relid, &detach_pending); if (!OidIsValid(result)) elog(ERROR, "could not find tuple for parent of relation %u", relid); @@ -68,8 +62,6 @@ get_partition_parent(Oid relid, bool even_if_detached) elog(ERROR, "relation %u has no parent because it's being detached", relid); - table_close(catalogRelation, AccessShareLock); - return result; } @@ -82,27 +74,16 @@ get_partition_parent(Oid relid, bool even_if_detached) * original parent is still returned.) */ static Oid -get_partition_parent_worker(Relation inhRel, Oid relid, bool *detach_pending) +get_partition_parent_worker(Oid relid, bool *detach_pending) { - SysScanDesc scan; - ScanKeyData key[2]; Oid result = InvalidOid; HeapTuple tuple; *detach_pending = false; - ScanKeyInit(&key[0], - Anum_pg_inherits_inhrelid, - BTEqualStrategyNumber, F_OIDEQ, - ObjectIdGetDatum(relid)); - ScanKeyInit(&key[1], - Anum_pg_inherits_inhseqno, - BTEqualStrategyNumber, F_INT4EQ, - Int32GetDatum(1)); - - scan = systable_beginscan(inhRel, InheritsRelidSeqnoIndexId, true, - NULL, 2, key); - tuple = systable_getnext(scan); + tuple = SearchSysCache2(INHRELIDSEQNO, + ObjectIdGetDatum(relid), + Int32GetDatum(1)); if (HeapTupleIsValid(tuple)) { Form_pg_inherits form = (Form_pg_inherits) GETSTRUCT(tuple); @@ -111,10 +92,9 @@ get_partition_parent_worker(Relation inhRel, Oid relid, bool *detach_pending) if (form->inhdetachpending) *detach_pending = true; result = form->inhparent; + ReleaseSysCache(tuple); } - systable_endscan(scan); - return result; } @@ -134,13 +114,8 @@ List * get_partition_ancestors(Oid relid) { List *result = NIL; - Relation inhRel; - inhRel = table_open(InheritsRelationId, AccessShareLock); - - get_partition_ancestors_worker(inhRel, relid, &result); - - table_close(inhRel, AccessShareLock); + get_partition_ancestors_worker(relid, &result); return result; } @@ -150,7 +125,7 @@ get_partition_ancestors(Oid relid) * recursive worker for get_partition_ancestors */ static void -get_partition_ancestors_worker(Relation inhRel, Oid relid, List **ancestors) +get_partition_ancestors_worker(Oid relid, List **ancestors) { Oid parentOid; bool detach_pending; @@ -159,12 +134,12 @@ get_partition_ancestors_worker(Relation inhRel, Oid relid, List **ancestors) * Recursion ends at the topmost level, ie., when there's no parent; also * when the partition is being detached. */ - parentOid = get_partition_parent_worker(inhRel, relid, &detach_pending); + parentOid = get_partition_parent_worker(relid, &detach_pending); if (parentOid == InvalidOid || detach_pending) return; *ancestors = lappend_oid(*ancestors, parentOid); - get_partition_ancestors_worker(inhRel, parentOid, ancestors); + get_partition_ancestors_worker(parentOid, ancestors); } /* diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c index 73f8afc0755..4a3e3aea447 100644 --- a/src/backend/executor/execPartition.c +++ b/src/backend/executor/execPartition.c @@ -776,9 +776,6 @@ ExecInitPartitionInfo(ModifyTableState *mtstate, EState *estate, * Otherwise, if this index has no parent, track it for later, * in case REINDEX CONCURRENTLY is working on one of the * arbiters. - * - * XXX get_partition_ancestors is slow: it scans pg_inherits - * each time. Consider a syscache or some other way to cache? */ indexoid = RelationGetRelid(leaf_part_rri->ri_IndexRelationDescs[listidx]); ancestors = get_partition_ancestors(indexoid); diff --git a/src/include/catalog/pg_inherits.h b/src/include/catalog/pg_inherits.h index c14aee773c3..5a785eca1cf 100644 --- a/src/include/catalog/pg_inherits.h +++ b/src/include/catalog/pg_inherits.h @@ -47,6 +47,7 @@ typedef FormData_pg_inherits *Form_pg_inherits; DECLARE_UNIQUE_INDEX_PKEY(pg_inherits_relid_seqno_index, 2680, InheritsRelidSeqnoIndexId, pg_inherits, btree(inhrelid oid_ops, inhseqno int4_ops)); DECLARE_INDEX(pg_inherits_parent_index, 2187, InheritsParentIndexId, pg_inherits, btree(inhparent oid_ops)); +MAKE_SYSCACHE(INHRELIDSEQNO, pg_inherits_relid_seqno_index, 16); extern List *find_inheritance_children(Oid parentrelId, LOCKMODE lockmode); extern List *find_inheritance_children_extended(Oid parentrelId, bool omit_detached, -- 2.43.0