From e0b457866e503a1b70b94c540147026b652fb019 Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Fri, 13 Nov 2020 13:39:31 -0300 Subject: [PATCH v3] Avoid errors in brin summarization.. ..which can happen if an index is reindexed concurrently --- src/backend/access/brin/brin.c | 37 ++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 11 deletions(-) diff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c index 1f72562c60..4d012ebd76 100644 --- a/src/backend/access/brin/brin.c +++ b/src/backend/access/brin/brin.c @@ -33,6 +33,7 @@ #include "postmaster/autovacuum.h" #include "storage/bufmgr.h" #include "storage/freespace.h" +#include "storage/lmgr.h" #include "utils/acl.h" #include "utils/builtins.h" #include "utils/index_selfuncs.h" @@ -886,21 +887,35 @@ brin_summarize_range(PG_FUNCTION_ARGS) /* * We must lock table before index to avoid deadlocks. However, if the - * passed indexoid isn't an index then IndexGetRelation() will fail. - * Rather than emitting a not-very-helpful error message, postpone - * complaining, expecting that the is-it-an-index test below will fail. + * passed indexoid isn't an index, then IndexGetRelation(false) would + * emit a not-very-helpful error message. Instead, postpone complaining + * until the is-it-an-index test, below. */ heapoid = IndexGetRelation(indexoid, true); - if (OidIsValid(heapoid)) - heapRel = table_open(heapoid, ShareUpdateExclusiveLock); - else - heapRel = NULL; + if (heapoid != InvalidOid) + LockRelationOid(heapoid, ShareUpdateExclusiveLock); - indexRel = index_open(indexoid, ShareUpdateExclusiveLock); + /* Now we can open the index; silently skip if it's gone. */ + indexRel = try_relation_open(indexoid, ShareUpdateExclusiveLock); + if (!indexRel) + { + if (heapoid != InvalidOid) + UnlockRelationOid(heapoid, ShareUpdateExclusiveLock); + PG_RETURN_INT32(0); + } + + /* If passed a non-index, fail noisily */ + if (indexRel->rd_rel->relkind != RELKIND_INDEX) + ereport(ERROR, + (errcode(ERRCODE_WRONG_OBJECT_TYPE), + errmsg("\"%s\" is not an index", + RelationGetRelationName(indexRel)))); + + /* Now we can open the table */ + heapRel = table_open(heapoid, NoLock); /* Must be a BRIN index */ - if (indexRel->rd_rel->relkind != RELKIND_INDEX || - indexRel->rd_rel->relam != BRIN_AM_OID) + if (indexRel->rd_rel->relam != BRIN_AM_OID) ereport(ERROR, (errcode(ERRCODE_WRONG_OBJECT_TYPE), errmsg("\"%s\" is not a BRIN index", @@ -916,7 +931,7 @@ brin_summarize_range(PG_FUNCTION_ARGS) * barely possible that a race against an index drop/recreation could have * netted us the wrong table. Recheck. */ - if (heapRel == NULL || heapoid != IndexGetRelation(indexoid, false)) + if (heapoid != IndexGetRelation(indexoid, false)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_TABLE), errmsg("could not open parent table of index %s", -- 2.20.1