Create ResultRelInfos later in InitPlan, index them by RT index.

Instead of allocating all the ResultRelInfos upfront in one big array,
allocate them in ExecInitModifyTable(). es_result_relations is now an
array of ResultRelInfo pointers, rather than an array of structs, and it
is indexed by the RT index.

This simplifies things: we get rid of the separate concept of a "result
rel index", and don't need to set it in setrefs.c anymore. This also
allows follow-up optimizations (not included in this commit yet) to skip
initializing ResultRelInfos for target relations that were not needed at
runtime, and removal of the es_result_relation_info pointer.

The EState arrays of regular result rels and root result rels are merged
into one array. Similarly, the resultRelations and rootResultRelations
lists in PlannedStmt are merged into one. It's not actually clear to me
why they were kept separate in the first place, but now that the
es_result_relations array is indexed by RT index, it certainly seems
pointless.

The PlannedStmt->resultRelations list is now only needed for
ExecRelationIsTargetRelation(). One visible effect of this change is that
ExecRelationIsTargetRelation() will now return 'true' also for the
partition root, if a partitioned table is updated. That seems like a good
thing, although the function isn't used in core code, and I don't see any
reason for an FDW to call it on a partition root.

Author: Amit Langote
Discussion: https://www.postgresql.org/message-id/CA%2BHiwqGEmiib8FLiHMhKB%2BCH5dRgHSLc5N5wnvc4kym%2BZYpQEQ%40mail.gmail.com

4 files changed, 11 insertions, 22 deletions

diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 415e117407c..c283bf14541 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -191,7 +191,6 @@ extern void InitResultRelInfo(ResultRelInfo *resultRelInfo,
 							  Relation partition_root,
 							  int instrument_options);
 extern ResultRelInfo *ExecGetTriggerResultRel(EState *estate, Oid relid);
-extern void ExecCleanUpTriggerState(EState *estate);
 extern void ExecConstraints(ResultRelInfo *resultRelInfo,
 							TupleTableSlot *slot, EState *estate);
 extern bool ExecPartitionCheck(ResultRelInfo *resultRelInfo,
@@ -538,6 +537,8 @@ extern bool ExecRelationIsTargetRelation(EState *estate, Index scanrelid);
 extern Relation ExecOpenScanRelation(EState *estate, Index scanrelid, int eflags);
 
 extern void ExecInitRangeTable(EState *estate, List *rangeTable);
+extern void ExecCloseRangeTableRelations(EState *estate);
+extern void ExecCloseResultRelations(EState *estate);
 
 static inline RangeTblEntry *
 exec_rt_fetch(Index rti, EState *estate)
@@ -546,6 +547,8 @@ exec_rt_fetch(Index rti, EState *estate)
 }
 
 extern Relation ExecGetRangeTableRelation(EState *estate, Index rti);
+extern void ExecInitResultRelation(EState *estate, ResultRelInfo *resultRelInfo,
+								   Index rti);
 
 extern int	executor_errposition(EState *estate, int location);
 
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index ef448d67c77..a926ff17118 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -519,23 +519,19 @@ typedef struct EState
 	CommandId	es_output_cid;
 
 	/* Info about target table(s) for insert/update/delete queries: */
-	ResultRelInfo *es_result_relations; /* array of ResultRelInfos */
-	int			es_num_result_relations;	/* length of array */
+	ResultRelInfo **es_result_relations;	/* Array of per-range-table-entry
+											 * ResultRelInfo pointers, or NULL
+											 * if not a target table */
+	List	   *es_opened_result_relations; /* List of non-NULL entries in
+											 * es_result_relations in no
+											 * specific order */
 	ResultRelInfo *es_result_relation_info; /* currently active array elt */
 
-	/*
-	 * Info about the partition root table(s) for insert/update/delete queries
-	 * targeting partitioned tables.  Only leaf partitions are mentioned in
-	 * es_result_relations, but we need access to the roots for firing
-	 * triggers and for runtime tuple routing.
-	 */
-	ResultRelInfo *es_root_result_relations;	/* array of ResultRelInfos */
-	int			es_num_root_result_relations;	/* length of the array */
 	PartitionDirectory es_partition_directory;	/* for PartitionDesc lookup */
 
 	/*
 	 * The following list contains ResultRelInfos created by the tuple routing
-	 * code for partitions that don't already have one.
+	 * code for partitions that aren't found in the es_result_relations array.
 	 */
 	List	   *es_tuple_routing_result_relations;
 
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index dbe86e7af65..3dd16b9ad53 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -120,8 +120,6 @@ typedef struct PlannerGlobal
 
 	List	   *resultRelations;	/* "flat" list of integer RT indexes */
 
-	List	   *rootResultRelations;	/* "flat" list of integer RT indexes */
-
 	List	   *appendRelations;	/* "flat" list of AppendRelInfos */
 
 	List	   *relationOids;	/* OIDs of relations the plan depends on */
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 83e01074ed1..a7bdf3497e1 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -68,12 +68,6 @@ typedef struct PlannedStmt
 	/* rtable indexes of target relations for INSERT/UPDATE/DELETE */
 	List	   *resultRelations;	/* integer list of RT indexes, or NIL */
 
-	/*
-	 * rtable indexes of partitioned table roots that are UPDATE/DELETE
-	 * targets; needed for trigger firing.
-	 */
-	List	   *rootResultRelations;
-
 	List	   *appendRelations;	/* list of AppendRelInfo nodes */
 
 	List	   *subplans;		/* Plan trees for SubPlan expressions; note
@@ -224,8 +218,6 @@ typedef struct ModifyTable
 	Index		rootRelation;	/* Root RT index, if target is partitioned */
 	bool		partColsUpdated;	/* some part key in hierarchy updated */
 	List	   *resultRelations;	/* integer list of RT indexes */
-	int			resultRelIndex; /* index of first resultRel in plan's list */
-	int			rootResultRelIndex; /* index of the partitioned table root */
 	List	   *plans;			/* plan(s) producing source data */
 	List	   *withCheckOptionLists;	/* per-target-table WCO lists */
 	List	   *returningLists; /* per-target-table RETURNING tlists */