From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 4 Apr 2022 16:38:51 +0000 (-0400)
Subject: Disable synchronize_seqscans in 027_stream_regress.pl.
X-Git-Tag: REL_15_BETA1~313
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cbf4177f2ca0b9bbfdb78a6ab51e3876e9ff6eac;p=thirdparty%2Fpostgresql.git

Disable synchronize_seqscans in 027_stream_regress.pl.

This script runs the core regression tests with quite a small value of
shared_buffers, making it prone to breakage due to synchronize_seqscans
kicking in where the tests don't expect that.  Disable that feature to
stabilize the tests.

Discussion: https://postgr.es/m/1258185.1648876239@sss.pgh.pa.us
---

diff --git a/src/test/recovery/t/027_stream_regress.pl b/src/test/recovery/t/027_stream_regress.pl
index aa972f89584..be9799c0a46 100644
--- a/src/test/recovery/t/027_stream_regress.pl
+++ b/src/test/recovery/t/027_stream_regress.pl
@@ -16,8 +16,14 @@ if (PostgreSQL::Test::Utils::has_wal_read_bug)
 # Initialize primary node
 my $node_primary = PostgreSQL::Test::Cluster->new('primary');
 $node_primary->init(allows_streaming => 1);
+
+# Increase some settings that Cluster->new makes too low by default.
 $node_primary->adjust_conf('postgresql.conf', 'max_connections', '25');
 $node_primary->append_conf('postgresql.conf', 'max_prepared_transactions = 10');
+# We'll stick with Cluster->new's small default shared_buffers, but since that
+# makes synchronized seqscans more probable, it risks changing the results of
+# some test queries.  Disable synchronized seqscans to prevent that.
+$node_primary->append_conf('postgresql.conf', 'synchronize_seqscans = off');
 
 # WAL consistency checking is resource intensive so require opt-in with the
 # PG_TEST_EXTRA environment variable.