From 35c85c3c9b90eb70937c8f409d2e7615b2bdb538 Mon Sep 17 00:00:00 2001 From: Masahiko Sawada Date: Tue, 25 Jul 2023 15:09:31 +0900 Subject: [PATCH] Remove unnecessary checks for indexes for REPLICA IDENTITY FULL tables. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Previously, when selecting an usable index for update/delete for the REPLICA IDENTITY FULL table, in IsIndexOnlyExpression(), we used to check if all index fields are not expressions. However, it was not necessary, because it is enough to check if only the leftmost index field is not an expression (and references the remote table column) and this check has already been done by RemoteRelContainsLeftMostColumnOnIdx(). This commit removes IsIndexOnlyExpression() and RemoteRelContainsLeftMostColumnOnIdx() and all checks for usable indexes for REPLICA IDENTITY FULL tables are now performed by IsIndexUsableForReplicaIdentityFull(). Backpatch this to remain the code consistent. Reported-by: Peter Smith Reviewed-by: Amit Kapila, Önder Kalacı Discussion: https://postgr.es/m/CAHut%2BPsGRE5WSsY0jcLHJEoA17MrbP9yy8FxdjC_ZOAACxbt%2BQ%40mail.gmail.com Backpatch-through: 16 --- src/backend/executor/execReplication.c | 9 -- src/backend/replication/logical/relation.c | 128 +++++++++------------ src/backend/replication/logical/worker.c | 24 +++- src/include/replication/logicalrelation.h | 2 +- 4 files changed, 73 insertions(+), 90 deletions(-) diff --git a/src/backend/executor/execReplication.c b/src/backend/executor/execReplication.c index af09342881..25d2868744 100644 --- a/src/backend/executor/execReplication.c +++ b/src/backend/executor/execReplication.c @@ -175,16 +175,7 @@ retry: if (!isIdxSafeToSkipDuplicates) { if (eq == NULL) - { -#ifdef USE_ASSERT_CHECKING - /* apply assertions only once for the input idxoid */ - IndexInfo *indexInfo = BuildIndexInfo(idxrel); - - Assert(IsIndexUsableForReplicaIdentityFull(indexInfo)); -#endif - eq = palloc0(sizeof(*eq) * outslot->tts_tupleDescriptor->natts); - } if (!tuples_equal(outslot, searchslot, eq)) continue; diff --git a/src/backend/replication/logical/relation.c b/src/backend/replication/logical/relation.c index c545b90636..6edbd5643a 100644 --- a/src/backend/replication/logical/relation.c +++ b/src/backend/replication/logical/relation.c @@ -731,71 +731,9 @@ logicalrep_partition_open(LogicalRepRelMapEntry *root, return entry; } -/* - * Returns true if the given index consists only of expressions such as: - * CREATE INDEX idx ON table(foo(col)); - * - * Returns false even if there is one column reference: - * CREATE INDEX idx ON table(foo(col), col_2); - */ -static bool -IsIndexOnlyOnExpression(IndexInfo *indexInfo) -{ - for (int i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++) - { - AttrNumber attnum = indexInfo->ii_IndexAttrNumbers[i]; - - if (AttributeNumberIsValid(attnum)) - return false; - } - - return true; -} - -/* - * Returns true if the attrmap contains the leftmost column of the index. - * Otherwise returns false. - * - * attrmap is a map of local attributes to remote ones. We can consult this - * map to check whether the local index attribute has a corresponding remote - * attribute. - */ -static bool -RemoteRelContainsLeftMostColumnOnIdx(IndexInfo *indexInfo, AttrMap *attrmap) -{ - AttrNumber keycol; - - Assert(indexInfo->ii_NumIndexAttrs >= 1); - - keycol = indexInfo->ii_IndexAttrNumbers[0]; - if (!AttributeNumberIsValid(keycol)) - return false; - - if (attrmap->maplen <= AttrNumberGetAttrOffset(keycol)) - return false; - - return attrmap->attnums[AttrNumberGetAttrOffset(keycol)] >= 0; -} - /* * Returns the oid of an index that can be used by the apply worker to scan - * the relation. The index must be btree, non-partial, and the leftmost - * field must be a column (not an expression) that references the remote - * relation column. These limitations help to keep the index scan similar - * to PK/RI index scans. - * - * Note that the limitations of index scans for replica identity full only - * adheres to a subset of the limitations of PK/RI. For example, we support - * columns that are marked as [NULL] or we are not interested in the [NOT - * DEFERRABLE] aspect of constraints here. It works for us because we always - * compare the tuples for non-PK/RI index scans. See - * RelationFindReplTupleByIndex(). - * - * XXX: There are no fundamental problems for supporting non-btree indexes. - * We mostly need to relax the limitations in RelationFindReplTupleByIndex(). - * For partial indexes, the required changes are likely to be larger. If - * none of the tuples satisfy the expression for the index scan, we fall-back - * to sequential execution, which might not be a good idea in some cases. + * the relation. * * We expect to call this function when REPLICA IDENTITY FULL is defined for * the remote relation. @@ -812,19 +750,16 @@ FindUsableIndexForReplicaIdentityFull(Relation localrel, AttrMap *attrmap) { Oid idxoid = lfirst_oid(lc); bool isUsableIdx; - bool containsLeftMostCol; Relation idxRel; IndexInfo *idxInfo; idxRel = index_open(idxoid, AccessShareLock); idxInfo = BuildIndexInfo(idxRel); - isUsableIdx = IsIndexUsableForReplicaIdentityFull(idxInfo); - containsLeftMostCol = - RemoteRelContainsLeftMostColumnOnIdx(idxInfo, attrmap); + isUsableIdx = IsIndexUsableForReplicaIdentityFull(idxInfo, attrmap); index_close(idxRel, AccessShareLock); /* Return the first eligible index found */ - if (isUsableIdx && containsLeftMostCol) + if (isUsableIdx) return idxoid; } @@ -832,17 +767,60 @@ FindUsableIndexForReplicaIdentityFull(Relation localrel, AttrMap *attrmap) } /* - * Returns true if the index is usable for replica identity full. For details, - * see FindUsableIndexForReplicaIdentityFull. + * Returns true if the index is usable for replica identity full. + * + * The index must be btree, non-partial, and the leftmost field must be a + * column (not an expression) that references the remote relation column. + * These limitations help to keep the index scan similar to PK/RI index + * scans. + * + * attrmap is a map of local attributes to remote ones. We can consult this + * map to check whether the local index attribute has a corresponding remote + * attribute. + * + * Note that the limitations of index scans for replica identity full only + * adheres to a subset of the limitations of PK/RI. For example, we support + * columns that are marked as [NULL] or we are not interested in the [NOT + * DEFERRABLE] aspect of constraints here. It works for us because we always + * compare the tuples for non-PK/RI index scans. See + * RelationFindReplTupleByIndex(). + * + * XXX: There are no fundamental problems for supporting non-btree indexes. + * We mostly need to relax the limitations in RelationFindReplTupleByIndex(). + * For partial indexes, the required changes are likely to be larger. If + * none of the tuples satisfy the expression for the index scan, we fall-back + * to sequential execution, which might not be a good idea in some cases. */ bool -IsIndexUsableForReplicaIdentityFull(IndexInfo *indexInfo) +IsIndexUsableForReplicaIdentityFull(IndexInfo *indexInfo, AttrMap *attrmap) { - bool is_btree = (indexInfo->ii_Am == BTREE_AM_OID); - bool is_partial = (indexInfo->ii_Predicate != NIL); - bool is_only_on_expression = IsIndexOnlyOnExpression(indexInfo); + AttrNumber keycol; - return is_btree && !is_partial && !is_only_on_expression; + /* The index must be a Btree index */ + if (indexInfo->ii_Am != BTREE_AM_OID) + return false; + + /* The index must not be a partial index */ + if (indexInfo->ii_Predicate != NIL) + return false; + + Assert(indexInfo->ii_NumIndexAttrs >= 1); + + /* The leftmost index field must not be an expression */ + keycol = indexInfo->ii_IndexAttrNumbers[0]; + if (!AttributeNumberIsValid(keycol)) + return false; + + /* + * And the leftmost index field must reference the remote relation column. + * This is because if it doesn't, the sequential scan is favorable over + * index scan in most cases. + */ + if (attrmap->maplen <= AttrNumberGetAttrOffset(keycol) || + attrmap->attnums[AttrNumberGetAttrOffset(keycol)] < 0) + return false; + + return true; } /* diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c index cb6659fc61..832b1cf764 100644 --- a/src/backend/replication/logical/worker.c +++ b/src/backend/replication/logical/worker.c @@ -140,6 +140,7 @@ #include #include +#include "access/genam.h" #include "access/table.h" #include "access/tableam.h" #include "access/twophase.h" @@ -410,7 +411,7 @@ static void apply_handle_delete_internal(ApplyExecutionData *edata, ResultRelInfo *relinfo, TupleTableSlot *remoteslot, Oid localindexoid); -static bool FindReplTupleInLocalRel(EState *estate, Relation localrel, +static bool FindReplTupleInLocalRel(ApplyExecutionData *edata, Relation localrel, LogicalRepRelation *remoterel, Oid localidxoid, TupleTableSlot *remoteslot, @@ -2663,7 +2664,7 @@ apply_handle_update_internal(ApplyExecutionData *edata, EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1, NIL); ExecOpenIndices(relinfo, false); - found = FindReplTupleInLocalRel(estate, localrel, + found = FindReplTupleInLocalRel(edata, localrel, &relmapentry->remoterel, localindexoid, remoteslot, &localslot); @@ -2816,7 +2817,7 @@ apply_handle_delete_internal(ApplyExecutionData *edata, EvalPlanQualInit(&epqstate, estate, NULL, NIL, -1, NIL); ExecOpenIndices(relinfo, false); - found = FindReplTupleInLocalRel(estate, localrel, remoterel, localindexoid, + found = FindReplTupleInLocalRel(edata, localrel, remoterel, localindexoid, remoteslot, &localslot); /* If found delete it. */ @@ -2855,12 +2856,13 @@ apply_handle_delete_internal(ApplyExecutionData *edata, * Local tuple, if found, is returned in '*localslot'. */ static bool -FindReplTupleInLocalRel(EState *estate, Relation localrel, +FindReplTupleInLocalRel(ApplyExecutionData *edata, Relation localrel, LogicalRepRelation *remoterel, Oid localidxoid, TupleTableSlot *remoteslot, TupleTableSlot **localslot) { + EState *estate = edata->estate; bool found; /* @@ -2875,9 +2877,21 @@ FindReplTupleInLocalRel(EState *estate, Relation localrel, (remoterel->replident == REPLICA_IDENTITY_FULL)); if (OidIsValid(localidxoid)) + { +#ifdef USE_ASSERT_CHECKING + Relation idxrel = index_open(localidxoid, AccessShareLock); + + /* Index must be PK, RI, or usable for REPLICA IDENTITY FULL tables */ + Assert(GetRelationIdentityOrPK(idxrel) == localidxoid || + IsIndexUsableForReplicaIdentityFull(BuildIndexInfo(idxrel), + edata->targetRel->attrmap)); + index_close(idxrel, AccessShareLock); +#endif + found = RelationFindReplTupleByIndex(localrel, localidxoid, LockTupleExclusive, remoteslot, *localslot); + } else found = RelationFindReplTupleSeq(localrel, LockTupleExclusive, remoteslot, *localslot); @@ -2995,7 +3009,7 @@ apply_handle_tuple_routing(ApplyExecutionData *edata, bool found; /* Get the matching local tuple from the partition. */ - found = FindReplTupleInLocalRel(estate, partrel, + found = FindReplTupleInLocalRel(edata, partrel, &part_entry->remoterel, part_entry->localindexoid, remoteslot_part, &localslot); diff --git a/src/include/replication/logicalrelation.h b/src/include/replication/logicalrelation.h index 921b9974db..3f4d906d74 100644 --- a/src/include/replication/logicalrelation.h +++ b/src/include/replication/logicalrelation.h @@ -48,7 +48,7 @@ extern LogicalRepRelMapEntry *logicalrep_partition_open(LogicalRepRelMapEntry *r Relation partrel, AttrMap *map); extern void logicalrep_rel_close(LogicalRepRelMapEntry *rel, LOCKMODE lockmode); -extern bool IsIndexUsableForReplicaIdentityFull(IndexInfo *indexInfo); +extern bool IsIndexUsableForReplicaIdentityFull(IndexInfo *indexInfo, AttrMap *attrmap); extern Oid GetRelationIdentityOrPK(Relation rel); #endif /* LOGICALRELATION_H */