From 31fae9226061c3cc96a1a40485aeb20ff5184724 Mon Sep 17 00:00:00 2001
From: Mikhail Nikalayeu <mihailnikalayeu@gmail.com>
Date: Mon, 30 Dec 2024 16:37:12 +0100
Subject: [PATCH v37 6/7] Optimize auxiliary index handling

Skip unnecessary computations for auxiliary indices by:
- in the index-insert path, detect auxiliary indexes and bypass Datum value computation
- set indexUnchanged=false for auxiliary indices to avoid redundant checks

These optimizations reduce overhead during concurrent index operations.
---
 src/backend/catalog/index.c         | 9 +++++++++
 src/backend/executor/execIndexing.c | 5 ++++-
 src/include/nodes/execnodes.h       | 6 ++++--
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index f94e5314081..cea1eb0207b 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -2964,6 +2964,15 @@ FormIndexDatum(IndexInfo *indexInfo,
 	ListCell   *indexpr_item;
 	int			i;
 
+	/* Auxiliary index does not need any values to be computed */
+	if (unlikely(indexInfo->ii_Auxiliary))
+	{
+		Assert(indexInfo->ii_Am == STIR_AM_OID);
+		memset(values, 0, sizeof(Datum) * indexInfo->ii_NumIndexAttrs);
+		memset(isnull, true, sizeof(bool) * indexInfo->ii_NumIndexAttrs);
+		return;
+	}
+
 	if (indexInfo->ii_Expressions != NIL &&
 		indexInfo->ii_ExpressionsState == NIL)
 	{
diff --git a/src/backend/executor/execIndexing.c b/src/backend/executor/execIndexing.c
index eb383812901..2df77a0606d 100644
--- a/src/backend/executor/execIndexing.c
+++ b/src/backend/executor/execIndexing.c
@@ -439,8 +439,11 @@ ExecInsertIndexTuples(ResultRelInfo *resultRelInfo,
 		 * There's definitely going to be an index_insert() call for this
 		 * index.  If we're being called as part of an UPDATE statement,
 		 * consider if the 'indexUnchanged' = true hint should be passed.
+		 *
+		 * For auxiliary indexes, always pass false to skip value comparison checks,
+		 * since auxiliary indexes only store TIDs and don't track value changes.
 		 */
-		indexUnchanged = ((flags & EIIT_IS_UPDATE) &&
+		indexUnchanged = ((flags & EIIT_IS_UPDATE) && !indexInfo->ii_Auxiliary &&
 						  index_unchanged_by_update(resultRelInfo,
 													estate,
 													indexInfo,
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 12e9d0f7cd2..1b8d3b88f8a 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -169,8 +169,10 @@ typedef struct ExprState
  *		entries for a particular index.  Used for both index_build and
  *		retail creation of index entries.
  *
- * ii_Concurrent, ii_BrokenHotChain, ii_Auxiliary and ii_ParallelWorkers
- * are used only during index build; they're conventionally zeroed otherwise.
+ * ii_Concurrent, ii_BrokenHotChain, and ii_ParallelWorkers are used only
+ * during index build; they're conventionally zeroed otherwise.  ii_Auxiliary
+ * is also used during retail inserts to skip datum formation for auxiliary
+ * indexes.
  * ----------------
  */
 typedef struct IndexInfo
-- 
2.43.0

