From b6ae449d32c2b2ce7ec12605effc32b579497c2f Mon Sep 17 00:00:00 2001 From: Antonin Houska Date: Mon, 22 Jun 2026 09:34:05 +0200 Subject: [PATCH] Copy the relevant pg_attrdef catalog entries for the transient relation. The default values may be needed by the executor when processing the concurrent data changes. In particular, ExecInsertIndexTuples() needs it when determining the value of the 'indexUnchanged' hint for the index AM. Like in copy_index_constraints(), we make the new catalog entries dependent on the transient relation, so they are dropped along with it automatically. --- src/backend/commands/repack.c | 97 +++++++++++++++++++ .../injection_points/specs/repack.spec | 3 +- 2 files changed, 99 insertions(+), 1 deletion(-) diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c index 4d177c868bb..725efa236bc 100644 --- a/src/backend/commands/repack.c +++ b/src/backend/commands/repack.c @@ -48,6 +48,7 @@ #include "catalog/namespace.h" #include "catalog/objectaccess.h" #include "catalog/pg_am.h" +#include "catalog/pg_attrdef.h" #include "catalog/pg_constraint.h" #include "catalog/pg_inherits.h" #include "catalog/toasting.h" @@ -204,6 +205,7 @@ static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHea static List *build_new_indexes(Relation NewHeap, Relation OldHeap, List *OldIndexes); static void copy_index_constraints(Relation old_index, Oid new_index_id, Oid new_heap_id); +static void copy_attribute_defaults(Relation old_heap, Relation new_heap); static Relation process_single_relation(RepackStmt *stmt, LOCKMODE lockmode, bool isTopLevel, @@ -1083,6 +1085,13 @@ rebuild_relation(Relation OldHeap, Relation index, bool verbose, Assert(CheckRelationOidLockedByMe(OIDNewHeap, AccessExclusiveLock, false)); NewHeap = table_open(OIDNewHeap, NoLock); + /* + * Copy attribute defaults - the executor may need them, in order to + * process the concurrent data changes. In particular, this is related to + * ExecInsertIndexTuples(). + */ + copy_attribute_defaults(OldHeap, NewHeap); + /* Copy the heap data into the new table in the desired order */ copy_table_data(NewHeap, OldHeap, index, snapshot, verbose, &swap_toast_by_content, &frozenXid, &cutoffMulti); @@ -3434,6 +3443,94 @@ copy_index_constraints(Relation old_index, Oid new_index_id, Oid new_heap_id) CommandCounterIncrement(); } +/* + * Create a transient copy of attribute defaults for the transient table. + * + * Like above, the executor needs information on attribute defaults. Once the + * repacking is finished, the catalog entries we create here are dropped. + */ +static void +copy_attribute_defaults(Relation old_heap, Relation new_heap) +{ + Oid old_heap_id = RelationGetRelid(old_heap); + Oid new_heap_id = RelationGetRelid(new_heap); + ScanKeyData skey; + Relation rel; + Relation att_rel = NULL; + TupleDesc desc; + SysScanDesc scan; + HeapTuple tup; + ObjectAddress objrel; + + rel = table_open(AttrDefaultRelationId, RowExclusiveLock); + ObjectAddressSet(objrel, RelationRelationId, new_heap_id); + + ScanKeyInit(&skey, + Anum_pg_attrdef_adrelid, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(old_heap_id)); + scan = systable_beginscan(rel, AttrDefaultIndexId, true, + NULL, 1, &skey); + desc = RelationGetDescr(rel); + while (HeapTupleIsValid(tup = systable_getnext(scan))) + { + Form_pg_attrdef adform; + Oid oid; + Datum values[Natts_pg_attrdef] = {0}; + bool nulls[Natts_pg_attrdef] = {0}; + bool replaces[Natts_pg_attrdef] = {0}; + HeapTuple new_tup, att_tup, att_new_tup; + ObjectAddress objad; + Datum att_values[Natts_pg_attribute] = {0}; + bool att_nulls[Natts_pg_attribute] = {0}; + bool att_replaces[Natts_pg_attribute] = {0}; + + adform = (Form_pg_attrdef) GETSTRUCT(tup); + Assert(adform->adrelid == old_heap_id); + + oid = GetNewOidWithIndex(rel, AttrDefaultOidIndexId, + Anum_pg_attrdef_oid); + values[Anum_pg_attrdef_oid - 1] = ObjectIdGetDatum(oid); + replaces[Anum_pg_attrdef_oid - 1] = true; + values[Anum_pg_attrdef_adrelid - 1] = ObjectIdGetDatum(new_heap_id); + replaces[Anum_pg_attrdef_adrelid - 1] = true; + + new_tup = heap_modify_tuple(tup, desc, values, nulls, replaces); + + /* Insert it into the catalog. */ + CatalogTupleInsert(rel, new_tup); + + /* Create a dependency so it's removed when we drop the new heap. */ + ObjectAddressSet(objad, AttrDefaultRelationId, oid); + recordDependencyOn(&objad, &objrel, DEPENDENCY_AUTO); + + /* Set atthasdef - new heap has it cleared. */ + att_tup = SearchSysCache2(ATTNUM, + ObjectIdGetDatum(new_heap_id), + ObjectIdGetDatum(adform->adnum)); + if (!HeapTupleIsValid(att_tup)) + elog(ERROR, "cache lookup failed for attribute %d of relation %u", + adform->adnum, new_heap_id); + + att_values[Anum_pg_attribute_atthasdef - 1] = BoolGetDatum(true); + att_replaces[Anum_pg_attribute_atthasdef - 1] = true; + + if (att_rel == NULL) + att_rel = table_open(AttributeRelationId, RowExclusiveLock); + att_new_tup = heap_modify_tuple(att_tup, RelationGetDescr(att_rel), + att_values, att_nulls, att_replaces); + ReleaseSysCache(att_tup); + CatalogTupleUpdate(att_rel, &att_new_tup->t_self, att_new_tup); + } + systable_endscan(scan); + + table_close(rel, RowExclusiveLock); + if (att_rel) + table_close(att_rel, RowExclusiveLock); + + CommandCounterIncrement(); +} + /* * Try to start a background worker to perform logical decoding of data * changes applied to relation while REPACK CONCURRENTLY is copying its diff --git a/src/test/modules/injection_points/specs/repack.spec b/src/test/modules/injection_points/specs/repack.spec index d727a9b056b..7896d1456ad 100644 --- a/src/test/modules/injection_points/specs/repack.spec +++ b/src/test/modules/injection_points/specs/repack.spec @@ -3,7 +3,8 @@ setup { CREATE EXTENSION injection_points; - CREATE TABLE repack_test(i int PRIMARY KEY, j int); + CREATE TABLE repack_test(i int PRIMARY KEY, j int, + k int GENERATED ALWAYS AS (j * 2) STORED); INSERT INTO repack_test(i, j) VALUES (1, 1), (2, 2), (3, 3), (4, 4); CREATE TABLE relfilenodes(node oid); -- 2.52.0