From 2fbdf1b38bc54b297e0f885ca97e0c8f5c922e72 Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Wed, 5 Sep 2018 14:36:13 -0300 Subject: [PATCH] Simplify partitioned table creation vs. relcache In the original code, we were storing the pg_inherits row for a partitioned table too early: enough that we had a hack for relcache to avoid falling flat on its face while reading such a partial entry. If we finish the pg_class creation first and *then* store the pg_inherits entry, we don't need that hack. Also recognize that pg_class.relpartbound is not marked NOT NULL and therefore it's entirely possible to read null values, so having only Assert() protection isn't enough. Change those to if/elog tests instead. This qualifies as a robustness fix, so backpatch to pg11. In passing, remove one access that wasn't actually needed, and reword one message to be like all the others that check for the same thing. Reviewed-by: Amit Langote Discussion: https://postgr.es/m/20180903213916.hh6wasnrdg6xv2ud@alvherre.pgsql --- src/backend/commands/tablecmds.c | 10 +++------- src/backend/partitioning/partbounds.c | 3 ++- src/backend/utils/cache/partcache.c | 21 ++++----------------- 3 files changed, 9 insertions(+), 25 deletions(-) diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index f9e83c2456..a1cb15ca30 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -773,9 +773,6 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId, InvalidOid, typaddress); - /* Store inheritance information for new rel. */ - StoreCatalogInheritance(relationId, inheritOids, stmt->partbound != NULL); - /* * We must bump the command counter to make the newly-created relation * tuple visible for opening. @@ -869,6 +866,9 @@ DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId, heap_close(parent, NoLock); } + /* Store inheritance information for new rel. */ + StoreCatalogInheritance(relationId, inheritOids, stmt->partbound != NULL); + /* * Process the partitioning specification (if any) and store the partition * key information into the catalog. @@ -14703,10 +14703,6 @@ ATExecDetachPartition(Relation rel, RangeVar *name) RelationGetRelid(partRel)); Assert(((Form_pg_class) GETSTRUCT(tuple))->relispartition); - (void) SysCacheGetAttr(RELOID, tuple, Anum_pg_class_relpartbound, - &isnull); - Assert(!isnull); - /* Clear relpartbound and reset relispartition */ memset(new_val, 0, sizeof(new_val)); memset(new_null, false, sizeof(new_null)); diff --git a/src/backend/partitioning/partbounds.c b/src/backend/partitioning/partbounds.c index 9015a05d32..4ed9920618 100644 --- a/src/backend/partitioning/partbounds.c +++ b/src/backend/partitioning/partbounds.c @@ -1641,8 +1641,9 @@ get_qual_for_range(Relation parent, PartitionBoundSpec *spec, datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_relpartbound, &isnull); + if (isnull) + elog(ERROR, "null relpartbound for relation %u", inhrelid); - Assert(!isnull); bspec = (PartitionBoundSpec *) stringToNode(TextDatumGetCString(datum)); if (!IsA(bspec, PartitionBoundSpec)) diff --git a/src/backend/utils/cache/partcache.c b/src/backend/utils/cache/partcache.c index 115a9fe78f..e35a43405e 100644 --- a/src/backend/utils/cache/partcache.c +++ b/src/backend/utils/cache/partcache.c @@ -302,23 +302,11 @@ RelationBuildPartitionDesc(Relation rel) if (!HeapTupleIsValid(tuple)) elog(ERROR, "cache lookup failed for relation %u", inhrelid); - /* - * It is possible that the pg_class tuple of a partition has not been - * updated yet to set its relpartbound field. The only case where - * this happens is when we open the parent relation to check using its - * partition descriptor that a new partition's bound does not overlap - * some existing partition. - */ - if (!((Form_pg_class) GETSTRUCT(tuple))->relispartition) - { - ReleaseSysCache(tuple); - continue; - } - datum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_relpartbound, &isnull); - Assert(!isnull); + if (isnull) + elog(ERROR, "null relpartbound for relation %u", inhrelid); boundspec = (Node *) stringToNode(TextDatumGetCString(datum)); /* @@ -883,9 +871,8 @@ generate_partition_qual(Relation rel) boundDatum = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_relpartbound, &isnull); - if (isnull) /* should not happen */ - elog(ERROR, "relation \"%s\" has relpartbound = null", - RelationGetRelationName(rel)); + if (isnull) + elog(ERROR, "null relpartbound for relation %u", RelationGetRelid(rel)); bound = castNode(PartitionBoundSpec, stringToNode(TextDatumGetCString(boundDatum))); ReleaseSysCache(tuple);