From 20d3fe9009ddbbbb3da3a2da298f922054b43f8c Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 26 Oct 2020 11:36:53 -0400 Subject: In INSERT/UPDATE, use the table's real tuple descriptor as target. Previously, ExecInitModifyTable relied on ExecInitJunkFilter, and thence ExecCleanTypeFromTL, to build the target descriptor from the query tlist. While we just checked (in ExecCheckPlanOutput) that the tlist produces compatible output, this is not a great substitute for the relation's actual tuple descriptor that's available from the relcache. For one thing, dropped columns will not be correctly marked attisdropped; it's a bit surprising that we've gotten away with that this long. But the real reason for being concerned with this is that using the table's descriptor means that the slot will have correct attrmissing data, allowing us to revert the klugy fix of commit ba9f18abd. (This commit undoes that one's changes in trigger.c, but keeps the new test case.) Thus we can solve the bogus-trigger-tuple problem with fewer cycles rather than more. No back-patch, since this doesn't fix any additional bug, and it seems somewhat more likely to have unforeseen side effects than ba9f18abd's narrow fix. Discussion: https://postgr.es/m/16644-5da7ef98a7ac4545@postgresql.org --- src/backend/executor/nodeModifyTable.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) (limited to 'src/backend/executor/nodeModifyTable.c') diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c index a33423c896e..29e07b72287 100644 --- a/src/backend/executor/nodeModifyTable.c +++ b/src/backend/executor/nodeModifyTable.c @@ -2591,15 +2591,27 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags) TupleTableSlot *junkresslot; subplan = mtstate->mt_plans[i]->plan; - if (operation == CMD_INSERT || operation == CMD_UPDATE) - ExecCheckPlanOutput(resultRelInfo->ri_RelationDesc, - subplan->targetlist); junkresslot = ExecInitExtraTupleSlot(estate, NULL, table_slot_callbacks(resultRelInfo->ri_RelationDesc)); - j = ExecInitJunkFilter(subplan->targetlist, - junkresslot); + + /* + * For an INSERT or UPDATE, the result tuple must always match + * the target table's descriptor. For a DELETE, it won't + * (indeed, there's probably no non-junk output columns). + */ + if (operation == CMD_INSERT || operation == CMD_UPDATE) + { + ExecCheckPlanOutput(resultRelInfo->ri_RelationDesc, + subplan->targetlist); + j = ExecInitJunkFilterInsertion(subplan->targetlist, + RelationGetDescr(resultRelInfo->ri_RelationDesc), + junkresslot); + } + else + j = ExecInitJunkFilter(subplan->targetlist, + junkresslot); if (operation == CMD_UPDATE || operation == CMD_DELETE) { -- cgit v1.2.3