From 1d5caec221d85b8950a1ee3d8bb6fad262549ea6 Mon Sep 17 00:00:00 2001 From: Dean Rasheed Date: Sat, 30 Sep 2023 10:52:21 +0100 Subject: Fix EvalPlanQual rechecking during MERGE. Under some circumstances, concurrent MERGE operations could lead to inconsistent results, that varied according the plan chosen. This was caused by a lack of rowmarks on the source relation, which meant that EvalPlanQual rechecking was not guaranteed to return the same source tuples when re-running the join query. Fix by ensuring that preprocess_rowmarks() sets up PlanRowMarks for all non-target relations used in MERGE, in the same way that it does for UPDATE and DELETE. Per bug #18103. Back-patch to v15, where MERGE was introduced. Dean Rasheed, reviewed by Richard Guo. Discussion: https://postgr.es/m/18103-c4386baab8e355e3%40postgresql.org --- src/backend/executor/nodeModifyTable.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'src/backend/executor/nodeModifyTable.c') diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c index d21a178ad5a..f62d28ac608 100644 --- a/src/backend/executor/nodeModifyTable.c +++ b/src/backend/executor/nodeModifyTable.c @@ -4284,9 +4284,9 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags) /* * If we have any secondary relations in an UPDATE or DELETE, they need to - * be treated like non-locked relations in SELECT FOR UPDATE, ie, the - * EvalPlanQual mechanism needs to be told about them. Locate the - * relevant ExecRowMarks. + * be treated like non-locked relations in SELECT FOR UPDATE, i.e., the + * EvalPlanQual mechanism needs to be told about them. This also goes for + * the source relations in a MERGE. Locate the relevant ExecRowMarks. */ arowmarks = NIL; foreach(l, node->rowMarks) -- cgit v1.2.3