From 29ef2b310da9892fda075ff9ee12da7f92d5da6e Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 6 Oct 2018 15:49:37 -0400 Subject: Restore sane locking behavior during parallel query. Commit 9a3cebeaa changed things so that parallel workers didn't obtain any lock of their own on tables they access. That was clearly a bad idea, but I'd mistakenly supposed that it was the intended end result of the series of patches for simplifying the executor's lock management. Undo that change in relation_open(), and adjust ExecOpenScanRelation() so that it gets the correct lock if inside a parallel worker. In passing, clean up some more obsolete comments about when locks are acquired. Discussion: https://postgr.es/m/468c85d9-540e-66a2-1dde-fec2b741e688@lab.ntt.co.jp --- src/backend/access/heap/heapam.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'src/backend/access/heap') diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 727d6776e1..5f1a69ca53 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -1140,13 +1140,9 @@ relation_open(Oid relationId, LOCKMODE lockmode) /* * If we didn't get the lock ourselves, assert that caller holds one, * except in bootstrap mode where no locks are used. - * - * Also, parallel workers currently assume that their parent holds locks - * for tables used in the parallel query (a mighty shaky assumption). */ Assert(lockmode != NoLock || IsBootstrapProcessingMode() || - IsParallelWorker() || CheckRelationLockedByMe(r, AccessShareLock, true)); /* Make note that we've accessed a temporary relation */ -- cgit v1.2.1