Support data-modifying commands (INSERT/UPDATE/DELETE) in WITH.

This patch implements data-modifying WITH queries according to the
semantics that the updates all happen with the same command counter value,
and in an unspecified order.  Therefore one WITH clause can't see the
effects of another, nor can the outer query see the effects other than
through the RETURNING values.  And attempts to do conflicting updates will
have unpredictable results.  We'll need to document all that.

This commit just fixes the code; documentation updates are waiting on
author.

Marko Tiikkaja and Hitoshi Harada

1 files changed, 104 insertions, 47 deletions

diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 12a5b2a8953..cf32dc56903 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -160,7 +160,8 @@ ExecProcessReturning(ProjectionInfo *projectReturning,
 static TupleTableSlot *
 ExecInsert(TupleTableSlot *slot,
 		   TupleTableSlot *planSlot,
-		   EState *estate)
+		   EState *estate,
+		   bool canSetTag)
 {
 	HeapTuple	tuple;
 	ResultRelInfo *resultRelInfo;
@@ -247,9 +248,12 @@ ExecInsert(TupleTableSlot *slot,
 												   estate);
 	}
 
-	(estate->es_processed)++;
-	estate->es_lastoid = newId;
-	setLastTid(&(tuple->t_self));
+	if (canSetTag)
+	{
+		(estate->es_processed)++;
+		estate->es_lastoid = newId;
+		setLastTid(&(tuple->t_self));
+	}
 
 	/* AFTER ROW INSERT Triggers */
 	ExecARInsertTriggers(estate, resultRelInfo, tuple, recheckIndexes);
@@ -283,7 +287,8 @@ ExecDelete(ItemPointer tupleid,
 		   HeapTupleHeader oldtuple,
 		   TupleTableSlot *planSlot,
 		   EPQState *epqstate,
-		   EState *estate)
+		   EState *estate,
+		   bool canSetTag)
 {
 	ResultRelInfo *resultRelInfo;
 	Relation	resultRelationDesc;
@@ -393,7 +398,8 @@ ldelete:;
 		 */
 	}
 
-	(estate->es_processed)++;
+	if (canSetTag)
+		(estate->es_processed)++;
 
 	/* AFTER ROW DELETE Triggers */
 	ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
@@ -467,7 +473,8 @@ ExecUpdate(ItemPointer tupleid,
 		   TupleTableSlot *slot,
 		   TupleTableSlot *planSlot,
 		   EPQState *epqstate,
-		   EState *estate)
+		   EState *estate,
+		   bool canSetTag)
 {
 	HeapTuple	tuple;
 	ResultRelInfo *resultRelInfo;
@@ -621,7 +628,8 @@ lreplace:;
 												   estate);
 	}
 
-	(estate->es_processed)++;
+	if (canSetTag)
+		(estate->es_processed)++;
 
 	/* AFTER ROW UPDATE Triggers */
 	ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple,
@@ -647,16 +655,13 @@ fireBSTriggers(ModifyTableState *node)
 	switch (node->operation)
 	{
 		case CMD_INSERT:
-			ExecBSInsertTriggers(node->ps.state,
-								 node->ps.state->es_result_relations);
+			ExecBSInsertTriggers(node->ps.state, node->resultRelInfo);
 			break;
 		case CMD_UPDATE:
-			ExecBSUpdateTriggers(node->ps.state,
-								 node->ps.state->es_result_relations);
+			ExecBSUpdateTriggers(node->ps.state, node->resultRelInfo);
 			break;
 		case CMD_DELETE:
-			ExecBSDeleteTriggers(node->ps.state,
-								 node->ps.state->es_result_relations);
+			ExecBSDeleteTriggers(node->ps.state, node->resultRelInfo);
 			break;
 		default:
 			elog(ERROR, "unknown operation");
@@ -673,16 +678,13 @@ fireASTriggers(ModifyTableState *node)
 	switch (node->operation)
 	{
 		case CMD_INSERT:
-			ExecASInsertTriggers(node->ps.state,
-								 node->ps.state->es_result_relations);
+			ExecASInsertTriggers(node->ps.state, node->resultRelInfo);
 			break;
 		case CMD_UPDATE:
-			ExecASUpdateTriggers(node->ps.state,
-								 node->ps.state->es_result_relations);
+			ExecASUpdateTriggers(node->ps.state, node->resultRelInfo);
 			break;
 		case CMD_DELETE:
-			ExecASDeleteTriggers(node->ps.state,
-								 node->ps.state->es_result_relations);
+			ExecASDeleteTriggers(node->ps.state, node->resultRelInfo);
 			break;
 		default:
 			elog(ERROR, "unknown operation");
@@ -703,6 +705,8 @@ ExecModifyTable(ModifyTableState *node)
 {
 	EState	   *estate = node->ps.state;
 	CmdType		operation = node->operation;
+	ResultRelInfo *saved_resultRelInfo;
+	ResultRelInfo *resultRelInfo;
 	PlanState  *subplanstate;
 	JunkFilter *junkfilter;
 	TupleTableSlot *slot;
@@ -712,6 +716,15 @@ ExecModifyTable(ModifyTableState *node)
 	HeapTupleHeader	oldtuple = NULL;
 
 	/*
+	 * If we've already completed processing, don't try to do more.  We need
+	 * this test because ExecPostprocessPlan might call us an extra time, and
+	 * our subplan's nodes aren't necessarily robust against being called
+	 * extra times.
+	 */
+	if (node->mt_done)
+		return NULL;
+
+	/*
 	 * On first call, fire BEFORE STATEMENT triggers before proceeding.
 	 */
 	if (node->fireBSTriggers)
@@ -720,17 +733,21 @@ ExecModifyTable(ModifyTableState *node)
 		node->fireBSTriggers = false;
 	}
 
+	/* Preload local variables */
+	resultRelInfo = node->resultRelInfo + node->mt_whichplan;
+	subplanstate = node->mt_plans[node->mt_whichplan];
+	junkfilter = resultRelInfo->ri_junkFilter;
+
 	/*
 	 * es_result_relation_info must point to the currently active result
-	 * relation.  (Note we assume that ModifyTable nodes can't be nested.) We
-	 * want it to be NULL whenever we're not within ModifyTable, though.
+	 * relation while we are within this ModifyTable node.  Even though
+	 * ModifyTable nodes can't be nested statically, they can be nested
+	 * dynamically (since our subplan could include a reference to a modifying
+	 * CTE).  So we have to save and restore the caller's value.
 	 */
-	estate->es_result_relation_info =
-		estate->es_result_relations + node->mt_whichplan;
+	saved_resultRelInfo = estate->es_result_relation_info;
 
-	/* Preload local variables */
-	subplanstate = node->mt_plans[node->mt_whichplan];
-	junkfilter = estate->es_result_relation_info->ri_junkFilter;
+	estate->es_result_relation_info = resultRelInfo;
 
 	/*
 	 * Fetch rows from subplan(s), and execute the required table modification
@@ -754,9 +771,10 @@ ExecModifyTable(ModifyTableState *node)
 			node->mt_whichplan++;
 			if (node->mt_whichplan < node->mt_nplans)
 			{
-				estate->es_result_relation_info++;
+				resultRelInfo++;
 				subplanstate = node->mt_plans[node->mt_whichplan];
-				junkfilter = estate->es_result_relation_info->ri_junkFilter;
+				junkfilter = resultRelInfo->ri_junkFilter;
+				estate->es_result_relation_info = resultRelInfo;
 				EvalPlanQualSetPlan(&node->mt_epqstate, subplanstate->plan,
 									node->mt_arowmarks[node->mt_whichplan]);
 				continue;
@@ -778,7 +796,7 @@ ExecModifyTable(ModifyTableState *node)
 				Datum		datum;
 				bool		isNull;
 
-				if (estate->es_result_relation_info->ri_RelationDesc->rd_rel->relkind == RELKIND_RELATION)
+				if (resultRelInfo->ri_RelationDesc->rd_rel->relkind == RELKIND_RELATION)
 				{
 					datum = ExecGetJunkAttribute(slot,
 												 junkfilter->jf_junkAttNo,
@@ -814,15 +832,15 @@ ExecModifyTable(ModifyTableState *node)
 		switch (operation)
 		{
 			case CMD_INSERT:
-				slot = ExecInsert(slot, planSlot, estate);
+				slot = ExecInsert(slot, planSlot, estate, node->canSetTag);
 				break;
 			case CMD_UPDATE:
 				slot = ExecUpdate(tupleid, oldtuple, slot, planSlot,
-								  &node->mt_epqstate, estate);
+								  &node->mt_epqstate, estate, node->canSetTag);
 				break;
 			case CMD_DELETE:
 				slot = ExecDelete(tupleid, oldtuple, planSlot,
-								  &node->mt_epqstate, estate);
+								  &node->mt_epqstate, estate, node->canSetTag);
 				break;
 			default:
 				elog(ERROR, "unknown operation");
@@ -835,19 +853,21 @@ ExecModifyTable(ModifyTableState *node)
 		 */
 		if (slot)
 		{
-			estate->es_result_relation_info = NULL;
+			estate->es_result_relation_info = saved_resultRelInfo;
 			return slot;
 		}
 	}
 
-	/* Reset es_result_relation_info before exiting */
-	estate->es_result_relation_info = NULL;
+	/* Restore es_result_relation_info before exiting */
+	estate->es_result_relation_info = saved_resultRelInfo;
 
 	/*
 	 * We're done, but fire AFTER STATEMENT triggers before exiting.
 	 */
 	fireASTriggers(node);
 
+	node->mt_done = true;
+
 	return NULL;
 }
 
@@ -861,6 +881,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 	ModifyTableState *mtstate;
 	CmdType		operation = node->operation;
 	int			nplans = list_length(node->plans);
+	ResultRelInfo *saved_resultRelInfo;
 	ResultRelInfo *resultRelInfo;
 	TupleDesc	tupDesc;
 	Plan	   *subplan;
@@ -886,32 +907,59 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 	mtstate->ps.state = estate;
 	mtstate->ps.targetlist = NIL;		/* not actually used */
 
+	mtstate->operation = operation;
+	mtstate->canSetTag = node->canSetTag;
+	mtstate->mt_done = false;
+
 	mtstate->mt_plans = (PlanState **) palloc0(sizeof(PlanState *) * nplans);
+	mtstate->resultRelInfo = estate->es_result_relations + node->resultRelIndex;
 	mtstate->mt_arowmarks = (List **) palloc0(sizeof(List *) * nplans);
 	mtstate->mt_nplans = nplans;
-	mtstate->operation = operation;
+
 	/* set up epqstate with dummy subplan data for the moment */
 	EvalPlanQualInit(&mtstate->mt_epqstate, estate, NULL, NIL, node->epqParam);
 	mtstate->fireBSTriggers = true;
 
-	/* For the moment, assume our targets are exactly the global result rels */
-
 	/*
 	 * call ExecInitNode on each of the plans to be executed and save the
-	 * results into the array "mt_plans".  Note we *must* set
+	 * results into the array "mt_plans".  This is also a convenient place
+	 * to verify that the proposed target relations are valid and open their
+	 * indexes for insertion of new index entries.  Note we *must* set
 	 * estate->es_result_relation_info correctly while we initialize each
 	 * sub-plan; ExecContextForcesOids depends on that!
 	 */
-	estate->es_result_relation_info = estate->es_result_relations;
+	saved_resultRelInfo = estate->es_result_relation_info;
+
+	resultRelInfo = mtstate->resultRelInfo;
 	i = 0;
 	foreach(l, node->plans)
 	{
 		subplan = (Plan *) lfirst(l);
+
+		/*
+		 * Verify result relation is a valid target for the current operation
+		 */
+		CheckValidResultRel(resultRelInfo->ri_RelationDesc, operation);
+
+		/*
+		 * If there are indices on the result relation, open them and save
+		 * descriptors in the result relation info, so that we can add new
+		 * index entries for the tuples we add/update.  We need not do this
+		 * for a DELETE, however, since deletion doesn't affect indexes.
+		 */
+		if (resultRelInfo->ri_RelationDesc->rd_rel->relhasindex &&
+			operation != CMD_DELETE)
+			ExecOpenIndices(resultRelInfo);
+
+		/* Now init the plan for this result rel */
+		estate->es_result_relation_info = resultRelInfo;
 		mtstate->mt_plans[i] = ExecInitNode(subplan, estate, eflags);
-		estate->es_result_relation_info++;
+
+		resultRelInfo++;
 		i++;
 	}
-	estate->es_result_relation_info = NULL;
+
+	estate->es_result_relation_info = saved_resultRelInfo;
 
 	/*
 	 * Initialize RETURNING projections if needed.
@@ -940,8 +988,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		/*
 		 * Build a projection for each result rel.
 		 */
-		Assert(list_length(node->returningLists) == estate->es_num_result_relations);
-		resultRelInfo = estate->es_result_relations;
+		resultRelInfo = mtstate->resultRelInfo;
 		foreach(l, node->returningLists)
 		{
 			List	   *rlist = (List *) lfirst(l);
@@ -1045,7 +1092,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 
 		if (junk_filter_needed)
 		{
-			resultRelInfo = estate->es_result_relations;
+			resultRelInfo = mtstate->resultRelInfo;
 			for (i = 0; i < nplans; i++)
 			{
 				JunkFilter *j;
@@ -1083,7 +1130,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		else
 		{
 			if (operation == CMD_INSERT)
-				ExecCheckPlanOutput(estate->es_result_relations->ri_RelationDesc,
+				ExecCheckPlanOutput(mtstate->resultRelInfo->ri_RelationDesc,
 									subplan->targetlist);
 		}
 	}
@@ -1096,6 +1143,16 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 	if (estate->es_trig_tuple_slot == NULL)
 		estate->es_trig_tuple_slot = ExecInitExtraTupleSlot(estate);
 
+	/*
+	 * Lastly, if this is not the primary (canSetTag) ModifyTable node, add it
+	 * to estate->es_auxmodifytables so that it will be run to completion by
+	 * ExecPostprocessPlan.  (It'd actually work fine to add the primary
+	 * ModifyTable node too, but there's no need.)
+	 */
+	if (!mtstate->canSetTag)
+		estate->es_auxmodifytables = lappend(estate->es_auxmodifytables,
+											 mtstate);
+
 	return mtstate;
 }