From: Alvaro Herrera Date: Wed, 15 Feb 2023 19:37:44 +0000 (+0100) Subject: Don't rely on uninitialized value in MERGE / DELETE X-Git-Tag: REL_15_3~126 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5d8ec1b9f625be800c8db93408e7c0553356fcd3;p=thirdparty%2Fpostgresql.git Don't rely on uninitialized value in MERGE / DELETE On MERGE / WHEN MATCHED DELETE it's not possible to get cross-partition updates, so we don't initialize cpUpdateRetrySlot; however, the code was not careful to ignore the value in that case. Make it do so. Backpatch to 15. Reported-by: Alexander Lakhin Reviewed-by: Dean Rasheed Discussion: https://postgr.es/m/17792-0f89452029662c36@postgresql.org --- diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c index 30fe932aee0..508dcc4cbea 100644 --- a/src/backend/executor/nodeModifyTable.c +++ b/src/backend/executor/nodeModifyTable.c @@ -2975,21 +2975,20 @@ lmerge_matched:; */ /* - * If cpUpdateRetrySlot is set, ExecCrossPartitionUpdate() - * must have detected that the tuple was concurrently - * updated, so we restart the search for an appropriate - * WHEN MATCHED clause to process the updated tuple. + * During an UPDATE, if cpUpdateRetrySlot is set, then + * ExecCrossPartitionUpdate() must have detected that the + * tuple was concurrently updated, so we restart the search + * for an appropriate WHEN MATCHED clause to process the + * updated tuple. * * In this case, ExecDelete() would already have performed * EvalPlanQual() on the latest version of the tuple, * which in turn would already have been loaded into * ri_oldTupleSlot, so no need to do either of those * things. - * - * XXX why do we not check the WHEN NOT MATCHED list in - * this case? */ - if (!TupIsNull(context->cpUpdateRetrySlot)) + if (commandType == CMD_UPDATE && + !TupIsNull(context->cpUpdateRetrySlot)) goto lmerge_matched; /*