From 942e441ee8f444bcc877ee7cdae00d5ecd312feb Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 30 Nov 2020 14:38:00 -0500 Subject: [PATCH] Prevent parallel index build in a standalone backend. This can't work if there's no postmaster, and indeed the code got an assertion failure trying. There should be a check on IsUnderPostmaster gating the use of parallelism, as the planner has for ordinary parallel queries. Commit 40d964ec9 got this right, so follow its model of checking IsUnderPostmaster at the same place where we check for max_parallel_maintenance_workers == 0. In general, new code implementing parallel utility operations should do the same. Report and patch by Yulin Pei, cosmetically adjusted by me. Back-patch to v11 where this code came in. Discussion: https://postgr.es/m/HK0PR01MB22747D839F77142D7E76A45DF4F50@HK0PR01MB2274.apcprd01.prod.exchangelabs.com --- src/backend/optimizer/plan/planner.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index 8e152078c5..a10bb89dcb 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -6090,8 +6090,12 @@ plan_create_index_workers(Oid tableOid, Oid indexOid) double reltuples; double allvisfrac; - /* Return immediately when parallelism disabled */ - if (dynamic_shared_memory_type == DSM_IMPL_NONE || + /* + * We don't allow performing parallel operation in standalone backend or + * when parallelism is disabled. + */ + if (!IsUnderPostmaster || + dynamic_shared_memory_type == DSM_IMPL_NONE || max_parallel_maintenance_workers == 0) return 0;