0003-Change-initdb-to-default-to-using-data-checksums.patch

From 8860636a97f49cbca88d45d26ce6955f9610460d Mon Sep 17 00:00:00 2001
From: Greg Sabino Mullane <greg@turnstep.com>
Date: Thu, 8 Aug 2024 12:32:17 -0400
Subject: [PATCH 3/3] Change initdb to default to using data checksums.

Also adjust the documentation and tests.
---
 doc/src/sgml/ref/initdb.sgml   |  4 +++-
 src/bin/initdb/initdb.c        |  2 +-
 src/bin/initdb/t/001_initdb.pl | 32 ++++++++++++++++++++++++--------
 3 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/doc/src/sgml/ref/initdb.sgml b/doc/src/sgml/ref/initdb.sgml
index bdd613e77f..2bd6e05df1 100644
--- a/doc/src/sgml/ref/initdb.sgml
+++ b/doc/src/sgml/ref/initdb.sgml
@@ -267,12 +267,14 @@ PostgreSQL documentation
        <para>
         Use checksums on data pages to help detect corruption by the
         I/O system that would otherwise be silent. Enabling checksums
-        may incur a noticeable performance penalty. If set, checksums
+        may incur a small performance penalty. If set, checksums
         are calculated for all objects, in all databases. All checksum
         failures will be reported in the
         <link linkend="monitoring-pg-stat-database-view">
         <structname>pg_stat_database</structname></link> view.
         See <xref linkend="checksums" /> for details.
+        Data checksums are enabled by default. They can be
+        disabled by use of <option>--no-data-checksums</option>.
        </para>
       </listitem>
      </varlistentry>
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 8ead7780f5..ce7d3e99e5 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -164,7 +164,7 @@ static bool noinstructions = false;
 static bool do_sync = true;
 static bool sync_only = false;
 static bool show_setting = false;
-static bool data_checksums = false;
+static bool data_checksums = true;
 static char *xlog_dir = NULL;
 static int	wal_segment_size_mb = (DEFAULT_XLOG_SEG_SIZE) / (1024 * 1024);
 static DataDirSyncMethod sync_method = DATA_DIR_SYNC_METHOD_FSYNC;
diff --git a/src/bin/initdb/t/001_initdb.pl b/src/bin/initdb/t/001_initdb.pl
index 06a35ac0b7..7345e66665 100644
--- a/src/bin/initdb/t/001_initdb.pl
+++ b/src/bin/initdb/t/001_initdb.pl
@@ -69,16 +69,11 @@ mkdir $datadir;
 	}
 }
 
-# Control file should tell that data checksums are disabled by default.
+# Control file should tell that data checksums are enabled by default.
 command_like(
 	[ 'pg_controldata', $datadir ],
-	qr/Data page checksum version:.*0/,
-	'checksums are disabled in control file');
-# pg_checksums fails with checksums disabled by default.  This is
-# not part of the tests included in pg_checksums to save from
-# the creation of an extra instance.
-command_fails([ 'pg_checksums', '-D', $datadir ],
-	"pg_checksums fails with data checksum disabled");
+	qr/Data page checksum version:.*1/,
+	'checksums are enabled in control file');
 
 command_ok([ 'initdb', '-S', $datadir ], 'sync only');
 command_fails([ 'initdb', $datadir ], 'existing data directory');
@@ -268,4 +263,25 @@ ok($conf !~ qr/^WORK_MEM = /m, "WORK_MEM should not be configured");
 ok($conf !~ qr/^Work_Mem = /m, "Work_Mem should not be configured");
 ok($conf =~ qr/^work_mem = 512/m, "work_mem should be in config");
 
+# Test the no-data-checksums flag
+
+my $datadir_nochecksums = "$tempdir/data_no_checksums";
+
+command_ok([ 'initdb', '--no-data-checksums', $datadir_nochecksums ],
+	'successful creation without data checksums');
+
+# Control file should tell that data checksums are disabled.
+command_like(
+	[ 'pg_controldata', $datadir_nochecksums ],
+	qr/Data page checksum version:.*0/,
+	'checksums are disabled in control file');
+
+# pg_checksums fails with checksums disabled. This is
+# not part of the tests included in pg_checksums to save from
+# the creation of an extra instance.
+command_fails(
+	[ 'pg_checksums', '-D', $datadir_nochecksums ],
+	"pg_checksums fails with data checksum disabled");
+
+
 done_testing();
-- 
2.30.2