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

1 files changed, 7 insertions, 11 deletions

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;