Remove new structure member from ResultRelInfo.

In commit ffbb7e65a, I added a ModifyTableState member to ResultRelInfo
to save the owning ModifyTableState for use by nodeModifyTable.c when
performing batch inserts, but as pointed out by Tom Lane, that changed
the array stride of es_result_relations, and that would break any
previously-compiled extension code that accesses that array.  Fix by
removing that member from ResultRelInfo and instead adding a List member
at the end of EState to save such ModifyTableStates.

Per report from Tom Lane.  Back-patch to v14, like the previous commit;
I chose to apply the patch to HEAD as well, to make back-patching easy.

Discussion: http://postgr.es/m/4065383.1669395453%40sss.pgh.pa.us

5 files changed, 22 insertions, 29 deletions

diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index ea64adc0259..ef2fd46092e 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1261,7 +1261,6 @@ InitResultRelInfo(ResultRelInfo *resultRelInfo,
 	resultRelInfo->ri_ChildToRootMap = NULL;
 	resultRelInfo->ri_ChildToRootMapValid = false;
 	resultRelInfo->ri_CopyMultiInsertBuffer = NULL;
-	resultRelInfo->ri_ModifyTableState = NULL;
 }
 
 /*
diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
index 7cc5b10f039..e03ea27299c 100644
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -1035,13 +1035,6 @@ ExecInitRoutingInfo(ModifyTableState *mtstate,
 
 	Assert(partRelInfo->ri_BatchSize >= 1);
 
-	/*
-	 * If doing batch insert, setup back-link so we can easily find the
-	 * mtstate again.
-	 */
-	if (partRelInfo->ri_BatchSize > 1)
-		partRelInfo->ri_ModifyTableState = mtstate;
-
 	partRelInfo->ri_CopyMultiInsertBuffer = NULL;
 
 	/*
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 0e595ffa6e5..358e5828831 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -127,9 +127,11 @@ CreateExecutorState(void)
 	estate->es_result_relations = NULL;
 	estate->es_opened_result_relations = NIL;
 	estate->es_tuple_routing_result_relations = NIL;
-	estate->es_insert_pending_result_relations = NIL;
 	estate->es_trig_target_relations = NIL;
 
+	estate->es_insert_pending_result_relations = NIL;
+	estate->es_insert_pending_modifytables = NIL;
+
 	estate->es_param_list_info = NULL;
 	estate->es_param_exec_vals = NULL;
 
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index ec84125aec3..8794528d6af 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -858,10 +858,12 @@ ExecInsert(ModifyTableContext *context,
 
 			/*
 			 * If these are the first tuples stored in the buffers, add the
-			 * target rel to the es_insert_pending_result_relations list,
-			 * except in the case where flushing was done above, in which case
-			 * the target rel would already have been added to the list, so no
-			 * need to do this.
+			 * target rel and the mtstate to the
+			 * es_insert_pending_result_relations and
+			 * es_insert_pending_modifytables lists respectively, execpt in
+			 * the case where flushing was done above, in which case they
+			 * would already have been added to the lists, so no need to do
+			 * this.
 			 */
 			if (resultRelInfo->ri_NumSlots == 0 && !flushed)
 			{
@@ -870,6 +872,8 @@ ExecInsert(ModifyTableContext *context,
 				estate->es_insert_pending_result_relations =
 					lappend(estate->es_insert_pending_result_relations,
 							resultRelInfo);
+				estate->es_insert_pending_modifytables =
+					lappend(estate->es_insert_pending_modifytables, mtstate);
 			}
 			Assert(list_member_ptr(estate->es_insert_pending_result_relations,
 								   resultRelInfo));
@@ -1219,12 +1223,14 @@ ExecBatchInsert(ModifyTableState *mtstate,
 static void
 ExecPendingInserts(EState *estate)
 {
-	ListCell   *lc;
+	ListCell   *l1,
+			   *l2;
 
-	foreach(lc, estate->es_insert_pending_result_relations)
+	forboth(l1, estate->es_insert_pending_result_relations,
+			l2, estate->es_insert_pending_modifytables)
 	{
-		ResultRelInfo *resultRelInfo = (ResultRelInfo *) lfirst(lc);
-		ModifyTableState *mtstate = resultRelInfo->ri_ModifyTableState;
+		ResultRelInfo *resultRelInfo = (ResultRelInfo *) lfirst(l1);
+		ModifyTableState *mtstate = (ModifyTableState *) lfirst(l2);
 
 		Assert(mtstate);
 		ExecBatchInsert(mtstate, resultRelInfo,
@@ -1236,7 +1242,9 @@ ExecPendingInserts(EState *estate)
 	}
 
 	list_free(estate->es_insert_pending_result_relations);
+	list_free(estate->es_insert_pending_modifytables);
 	estate->es_insert_pending_result_relations = NIL;
+	estate->es_insert_pending_modifytables = NIL;
 }
 
 /*
@@ -4342,13 +4350,6 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		}
 		else
 			resultRelInfo->ri_BatchSize = 1;
-
-		/*
-		 * If doing batch insert, setup back-link so we can easily find the
-		 * mtstate again.
-		 */
-		if (resultRelInfo->ri_BatchSize > 1)
-			resultRelInfo->ri_ModifyTableState = mtstate;
 	}
 
 	/*
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 05ec9f2bf75..580e99242be 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -556,9 +556,6 @@ typedef struct ResultRelInfo
 	 * one of its ancestors; see ExecCrossPartitionUpdateForeignKey().
 	 */
 	List	   *ri_ancestorResultRels;
-
-	/* for use by nodeModifyTable.c when performing batch-inserts */
-	struct ModifyTableState *ri_ModifyTableState;
 } ResultRelInfo;
 
 /* ----------------
@@ -682,10 +679,11 @@ typedef struct EState
 	struct JitInstrumentation *es_jit_worker_instr;
 
 	/*
-	 * The following list contains ResultRelInfos for foreign tables on which
-	 * batch-inserts are to be executed.
+	 * Lists of ResultRelInfos for foreign tables on which batch-inserts are
+	 * to be executed and owning ModifyTableStates, stored in the same order.
 	 */
 	List	   *es_insert_pending_result_relations;
+	List	   *es_insert_pending_modifytables;
 } EState;