v5-0001-BUFFER_USAGE_LIMIT-reduces-needed-test-table-size.patch

From 0ab9af06934ab551f2224493e913ae26000b3f87 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Sat, 6 May 2023 12:24:28 -0400
Subject: [PATCH v5 1/3] BUFFER_USAGE_LIMIT reduces needed test table size

Using the minimum BUFFER_USAGE_LIMIT value, the VACUUM ring buffer is
smaller and we can make one of the pg_stat_io test tables smaller while
still causing reuses.
---
 src/test/regress/expected/stats.out | 6 ++++--
 src/test/regress/sql/stats.sql      | 6 ++++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/test/regress/expected/stats.out b/src/test/regress/expected/stats.out
index 813d6d39ea..d4e4889e7b 100644
--- a/src/test/regress/expected/stats.out
+++ b/src/test/regress/expected/stats.out
@@ -1337,11 +1337,13 @@ SET wal_skip_threshold = '1 kB';
 SELECT sum(reuses) AS reuses, sum(reads) AS reads
   FROM pg_stat_io WHERE context = 'vacuum' \gset io_sum_vac_strategy_before_
 CREATE TABLE test_io_vac_strategy(a int, b int) WITH (autovacuum_enabled = 'false');
-INSERT INTO test_io_vac_strategy SELECT i, i from generate_series(1, 8000)i;
+INSERT INTO test_io_vac_strategy SELECT i, i from generate_series(1, 4500)i;
 -- Ensure that the next VACUUM will need to perform IO by rewriting the table
 -- first with VACUUM (FULL).
 VACUUM (FULL) test_io_vac_strategy;
-VACUUM (PARALLEL 0) test_io_vac_strategy;
+-- Use the minimum BUFFER_USAGE_LIMIT to cause reuses with the smallest table
+-- possible.
+VACUUM (PARALLEL 0, BUFFER_USAGE_LIMIT 128) test_io_vac_strategy;
 SELECT pg_stat_force_next_flush();
  pg_stat_force_next_flush 
 --------------------------
diff --git a/src/test/regress/sql/stats.sql b/src/test/regress/sql/stats.sql
index 99a28bb79c..7ba341314f 100644
--- a/src/test/regress/sql/stats.sql
+++ b/src/test/regress/sql/stats.sql
@@ -670,11 +670,13 @@ SET wal_skip_threshold = '1 kB';
 SELECT sum(reuses) AS reuses, sum(reads) AS reads
   FROM pg_stat_io WHERE context = 'vacuum' \gset io_sum_vac_strategy_before_
 CREATE TABLE test_io_vac_strategy(a int, b int) WITH (autovacuum_enabled = 'false');
-INSERT INTO test_io_vac_strategy SELECT i, i from generate_series(1, 8000)i;
+INSERT INTO test_io_vac_strategy SELECT i, i from generate_series(1, 4500)i;
 -- Ensure that the next VACUUM will need to perform IO by rewriting the table
 -- first with VACUUM (FULL).
 VACUUM (FULL) test_io_vac_strategy;
-VACUUM (PARALLEL 0) test_io_vac_strategy;
+-- Use the minimum BUFFER_USAGE_LIMIT to cause reuses with the smallest table
+-- possible.
+VACUUM (PARALLEL 0, BUFFER_USAGE_LIMIT 128) test_io_vac_strategy;
 SELECT pg_stat_force_next_flush();
 SELECT sum(reuses) AS reuses, sum(reads) AS reads
   FROM pg_stat_io WHERE context = 'vacuum' \gset io_sum_vac_strategy_after_
-- 
2.37.2