From 1d1777f6ace4ba7b2012d79b750751f861c8817e Mon Sep 17 00:00:00 2001
From: Antonin Houska <ah@cybertec.at>
Date: Fri, 12 Jul 2024 15:22:05 +0200
Subject: [PATCH] Check properly if indexes need to be updated.

In PG 16 it's possible to use HOT update even if indexed attributes change -
in particular, the attributes of "summarizing" indexes. Therefore, the check
for HOT update is not sufficient.
---
 NEWS         |  8 ++++++++
 concurrent.c | 14 ++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/NEWS b/NEWS
index 3ee7dcb..6941dc1 100644
--- a/NEWS
+++ b/NEWS
@@ -52,6 +52,14 @@ Bug fixes
    Like with other functions of this extension, the SUPERUSER role attribute
    is not needed for execution. The REPLICATION attribute is sufficient.
 
+4. Update BRIN indexes when appropriate.
+
+   If a row was updated during the table processing and only the attributes of
+   "summarizing" (BRIN) indexes changed, pg_squeeze might fail to update those
+   indexes.
+
+   This bug only affects pg_squeeze on PostgreSQL 16.
+
 
 Release 1.6.1
 =============
diff --git a/concurrent.c b/concurrent.c
index 6607a23..96b5a56 100644
--- a/concurrent.c
+++ b/concurrent.c
@@ -416,7 +416,21 @@ apply_concurrent_changes(DecodingOutputState *dstate, Relation relation,
 								   &update_indexes
 #endif
 					);
+				/*
+				 * In PG < 16, change of any indexed attribute makes HOT
+				 * impossible, Therefore HOT update implies that no index
+				 * needs to be updated.
+				 *
+				 * In PG >= 16, if only attributes of "summarizing indexes"
+				 * change, HOT update is still possible. Therefore HOT update
+				 * might still require some indexes (in particular, the
+				 * summarizing ones) to be updated.
+				 */
+#if PG_VERSION_NUM >= 160000
+				if (update_indexes != TU_None)
+#else
 				if (!HeapTupleIsHeapOnly(tup))
+#endif
 				{
 					List	   *recheck;