From: Michael Paquier <michael@paquier.xyz>
Date: Sun, 22 Mar 2026 06:24:33 +0000 (+0900)
Subject: Add test for single-page VACUUM of hash index on INSERT
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1f7947a48d0c4b802f986ac32dc0e95b6f7f8f8f;p=thirdparty%2Fpostgresql.git

Add test for single-page VACUUM of hash index on INSERT

_hash_vacuum_one_page() in hashinsert.c is a routine related to hash
indexes that can perform a single-page VACUUM when dead tuples are
detected during index insertion.  This routine previously had no test
coverage, and this commit adds a test case for that purpose.

To safely create dead tuples in a way that works with parallel tests,
this uses a technique based on a rollbacked INSERT, following a
suggestion by Heikki Linnakangas.

Author: Alexander Kuzmenkov <akuzmenkov@tigerdata.com>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/CALzhyqxrc1ZHYmf5V8NE+yMboqVg7xZrQM7K2c7VS0p1v8z42w@mail.gmail.com
---

diff --git a/src/test/regress/expected/hash_index.out b/src/test/regress/expected/hash_index.out
index 04035400f12..0b099b9e771 100644
--- a/src/test/regress/expected/hash_index.out
+++ b/src/test/regress/expected/hash_index.out
@@ -333,6 +333,27 @@ ROLLBACK;
 INSERT INTO hash_cleanup_heap SELECT 1 FROM generate_series(1, 50) as i;
 CHECKPOINT;
 VACUUM hash_cleanup_heap;
+-- Test cleanup of dead index tuples on single page with INSERT.
+TRUNCATE hash_cleanup_heap;
+INSERT INTO hash_cleanup_heap SELECT 1 FROM generate_series(1, 1000) as i;
+-- This relies on a rollbacked INSERT instead of a DELETE to make the creation
+-- of the dead tuples concurrent-safe.
+BEGIN;
+INSERT INTO hash_cleanup_heap SELECT 1 FROM generate_series(1, 500) as i;
+ROLLBACK;
+SET enable_seqscan = off;
+SET enable_bitmapscan = off;
+SELECT count(*) FROM hash_cleanup_heap WHERE keycol = 1;
+ count 
+-------
+  1000
+(1 row)
+
+-- This query checks the hash index pages for dead tuples where the data
+-- is inserted, and performs a local VACUUM on a single page.
+INSERT INTO hash_cleanup_heap SELECT 1 FROM generate_series(1, 200) as i;
+RESET enable_seqscan;
+RESET enable_bitmapscan;
 -- Clean up.
 DROP TABLE hash_cleanup_heap;
 -- Index on temp table.
diff --git a/src/test/regress/sql/hash_index.sql b/src/test/regress/sql/hash_index.sql
index 60571f6cdf1..3ebdaeaf172 100644
--- a/src/test/regress/sql/hash_index.sql
+++ b/src/test/regress/sql/hash_index.sql
@@ -314,6 +314,23 @@ INSERT INTO hash_cleanup_heap SELECT 1 FROM generate_series(1, 50) as i;
 CHECKPOINT;
 VACUUM hash_cleanup_heap;
 
+-- Test cleanup of dead index tuples on single page with INSERT.
+TRUNCATE hash_cleanup_heap;
+INSERT INTO hash_cleanup_heap SELECT 1 FROM generate_series(1, 1000) as i;
+-- This relies on a rollbacked INSERT instead of a DELETE to make the creation
+-- of the dead tuples concurrent-safe.
+BEGIN;
+INSERT INTO hash_cleanup_heap SELECT 1 FROM generate_series(1, 500) as i;
+ROLLBACK;
+SET enable_seqscan = off;
+SET enable_bitmapscan = off;
+SELECT count(*) FROM hash_cleanup_heap WHERE keycol = 1;
+-- This query checks the hash index pages for dead tuples where the data
+-- is inserted, and performs a local VACUUM on a single page.
+INSERT INTO hash_cleanup_heap SELECT 1 FROM generate_series(1, 200) as i;
+RESET enable_seqscan;
+RESET enable_bitmapscan;
+
 -- Clean up.
 DROP TABLE hash_cleanup_heap;