v47-0009-Track-opened-range-table-relations-in-a-List-in-.patch

From 1bc15cf1211111a6986e097f5a7ac3899c9a784b Mon Sep 17 00:00:00 2001
From: Amit Langote <amitlan@postgresql.org>
Date: Wed, 6 Sep 2023 17:54:19 +0900
Subject: [PATCH v47 9/9] Track opened range table relations in a List in
 EState

This makes ExecCloseRangeTableRelations faster when there are many
relations in the range table but only a few are opened during
execution, such as when run-time pruning kicks in on an Append
containing thousands of partition subplans.

Discussion: https://postgr.es/m/CA+HiwqFGkMSge6TgC9KQzde0ohpAycLQuV7ooitEEpbKB0O_mg@mail.gmail.com
---
 src/backend/executor/execMain.c  | 9 +++++----
 src/backend/executor/execUtils.c | 3 +++
 src/include/nodes/execnodes.h    | 2 ++
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 2804ec70f1..d559c1de61 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -1649,12 +1649,13 @@ ExecCloseResultRelations(EState *estate)
 void
 ExecCloseRangeTableRelations(EState *estate)
 {
-	int			i;
+	ListCell *lc;
 
-	for (i = 0; i < estate->es_range_table_size; i++)
+	foreach(lc, estate->es_opened_relations)
 	{
-		if (estate->es_relations[i])
-			table_close(estate->es_relations[i], NoLock);
+		Relation rel = lfirst(lc);
+
+		table_close(rel, NoLock);
 	}
 }
 
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 2b7a08c9ba..1dfef44495 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -822,6 +822,9 @@ ExecGetRangeTableRelation(EState *estate, Index rti)
 		}
 
 		estate->es_relations[rti - 1] = rel;
+		if (rel != NULL)
+			estate->es_opened_relations = lappend(estate->es_opened_relations,
+												  rel);
 	}
 
 	return rel;
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index bb5734edb5..8bbe1f6b14 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -619,6 +619,8 @@ typedef struct EState
 	Index		es_range_table_size;	/* size of the range table arrays */
 	Relation   *es_relations;	/* Array of per-range-table-entry Relation
 								 * pointers, or NULL if not yet opened */
+	List	   *es_opened_relations; /* List of non-NULL entries in
+									  * es_relations in no specific order */
 	struct ExecRowMark **es_rowmarks;	/* Array of per-range-table-entry
 										 * ExecRowMarks, or NULL if none */
 	List	   *es_rteperminfos;	/* List of RTEPermissionInfo */
-- 
2.35.3