Use ResultRelInfo ** rather than ResultRelInfo * for tuple routing.

The previous convention doesn't lend itself to creating ResultRelInfos
lazily, as we already do in ExecGetTriggerResultRel.  This patch
doesn't make anything lazier than before, but the pending patch for
UPDATE tuple routing proposes to do so (and there might be other
opportunities as well).

Amit Khandekar with some adjustments by me.

Discussion: http://postgr.es/m/CA+TgmoYPVP9Lyf6vUFA5DwxS4c--x6LOj2y36BsJaYtp62eXPQ@mail.gmail.com

1 files changed, 43 insertions, 31 deletions

diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 845c409540a..0027d21253f 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -303,7 +303,7 @@ ExecInsert(ModifyTableState *mtstate,
 		 * the selected partition.
 		 */
 		saved_resultRelInfo = resultRelInfo;
-		resultRelInfo = mtstate->mt_partitions + leaf_part_index;
+		resultRelInfo = mtstate->mt_partitions[leaf_part_index];
 
 		/* We do not yet have a way to insert into a foreign partition */
 		if (resultRelInfo->ri_FdwRoutine)
@@ -1498,25 +1498,11 @@ ExecSetupTransitionCaptureState(ModifyTableState *mtstate, EState *estate)
 	if (mtstate->mt_transition_capture != NULL ||
 		mtstate->mt_oc_transition_capture != NULL)
 	{
-		ResultRelInfo *resultRelInfos;
 		int			numResultRelInfos;
 
-		/* Find the set of partitions so that we can find their TupleDescs. */
-		if (mtstate->mt_partition_dispatch_info != NULL)
-		{
-			/*
-			 * For INSERT via partitioned table, so we need TupleDescs based
-			 * on the partition routing table.
-			 */
-			resultRelInfos = mtstate->mt_partitions;
-			numResultRelInfos = mtstate->mt_num_partitions;
-		}
-		else
-		{
-			/* Otherwise we need the ResultRelInfo for each subplan. */
-			resultRelInfos = mtstate->resultRelInfo;
-			numResultRelInfos = mtstate->mt_nplans;
-		}
+		numResultRelInfos = (mtstate->mt_partition_tuple_slot != NULL ?
+							 mtstate->mt_num_partitions :
+							 mtstate->mt_nplans);
 
 		/*
 		 * Build array of conversion maps from each child's TupleDesc to the
@@ -1526,12 +1512,36 @@ ExecSetupTransitionCaptureState(ModifyTableState *mtstate, EState *estate)
 		 */
 		mtstate->mt_transition_tupconv_maps = (TupleConversionMap **)
 			palloc0(sizeof(TupleConversionMap *) * numResultRelInfos);
-		for (i = 0; i < numResultRelInfos; ++i)
+
+		/* Choose the right set of partitions */
+		if (mtstate->mt_partition_dispatch_info != NULL)
 		{
-			mtstate->mt_transition_tupconv_maps[i] =
-				convert_tuples_by_name(RelationGetDescr(resultRelInfos[i].ri_RelationDesc),
-									   RelationGetDescr(targetRelInfo->ri_RelationDesc),
-									   gettext_noop("could not convert row type"));
+			/*
+			 * For tuple routing among partitions, we need TupleDescs based
+			 * on the partition routing table.
+			 */
+			ResultRelInfo **resultRelInfos = mtstate->mt_partitions;
+
+			for (i = 0; i < numResultRelInfos; ++i)
+			{
+				mtstate->mt_transition_tupconv_maps[i] =
+					convert_tuples_by_name(RelationGetDescr(resultRelInfos[i]->ri_RelationDesc),
+										   RelationGetDescr(targetRelInfo->ri_RelationDesc),
+										   gettext_noop("could not convert row type"));
+			}
+		}
+		else
+		{
+			/* Otherwise we need the ResultRelInfo for each subplan. */
+			ResultRelInfo *resultRelInfos = mtstate->resultRelInfo;
+
+			for (i = 0; i < numResultRelInfos; ++i)
+			{
+				mtstate->mt_transition_tupconv_maps[i] =
+					convert_tuples_by_name(RelationGetDescr(resultRelInfos[i].ri_RelationDesc),
+										   RelationGetDescr(targetRelInfo->ri_RelationDesc),
+										   gettext_noop("could not convert row type"));
+			}
 		}
 
 		/*
@@ -1935,7 +1945,7 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
 	{
 		PartitionDispatch *partition_dispatch_info;
-		ResultRelInfo *partitions;
+		ResultRelInfo **partitions;
 		TupleConversionMap **partition_tupconv_maps;
 		TupleTableSlot *partition_tuple_slot;
 		int			num_parted,
@@ -2014,14 +2024,16 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 			   mtstate->mt_nplans == 1);
 		wcoList = linitial(node->withCheckOptionLists);
 		plan = mtstate->mt_plans[0];
-		resultRelInfo = mtstate->mt_partitions;
 		for (i = 0; i < mtstate->mt_num_partitions; i++)
 		{
-			Relation	partrel = resultRelInfo->ri_RelationDesc;
+			Relation	partrel;
 			List	   *mapped_wcoList;
 			List	   *wcoExprs = NIL;
 			ListCell   *ll;
 
+			resultRelInfo = mtstate->mt_partitions[i];
+			partrel = resultRelInfo->ri_RelationDesc;
+
 			/* varno = node->nominalRelation */
 			mapped_wcoList = map_partition_varattnos(wcoList,
 													 node->nominalRelation,
@@ -2037,7 +2049,6 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 
 			resultRelInfo->ri_WithCheckOptions = mapped_wcoList;
 			resultRelInfo->ri_WithCheckOptionExprs = wcoExprs;
-			resultRelInfo++;
 		}
 	}
 
@@ -2088,13 +2099,15 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		 * will suffice.  This only occurs for the INSERT case; UPDATE/DELETE
 		 * are handled above.
 		 */
-		resultRelInfo = mtstate->mt_partitions;
 		returningList = linitial(node->returningLists);
 		for (i = 0; i < mtstate->mt_num_partitions; i++)
 		{
-			Relation	partrel = resultRelInfo->ri_RelationDesc;
+			Relation	partrel;
 			List	   *rlist;
 
+			resultRelInfo = mtstate->mt_partitions[i];
+			partrel = resultRelInfo->ri_RelationDesc;
+
 			/* varno = node->nominalRelation */
 			rlist = map_partition_varattnos(returningList,
 											node->nominalRelation,
@@ -2102,7 +2115,6 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 			resultRelInfo->ri_projectReturning =
 				ExecBuildProjectionInfo(rlist, econtext, slot, &mtstate->ps,
 										resultRelInfo->ri_RelationDesc->rd_att);
-			resultRelInfo++;
 		}
 	}
 	else
@@ -2376,7 +2388,7 @@ ExecEndModifyTable(ModifyTableState *node)
 	}
 	for (i = 0; i < node->mt_num_partitions; i++)
 	{
-		ResultRelInfo *resultRelInfo = node->mt_partitions + i;
+		ResultRelInfo *resultRelInfo = node->mt_partitions[i];
 
 		ExecCloseIndices(resultRelInfo);
 		heap_close(resultRelInfo->ri_RelationDesc, NoLock);