On 22/12/2018 00:38, Michael Paquier wrote:
> On Fri, Dec 21, 2018 at 01:54:20PM +0300, Sergei Kornilov wrote:
>> I am +1 for recovery_target_timeline=latest by default. This is
>> common case in my opinion.
>
> I agree also that switching to the latest timeline should be the
> default. People get confused because of the current default.
How about this patch then?
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>From 5fd266a61c63104d8f3f4cd3e19bfc99fd22ba21 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pete...@gmx.net>
Date: Thu, 27 Dec 2018 11:49:47 +0100
Subject: [PATCH] Always use latest timeline in standby mode
In standby mode, ignore the setting of recovery_target_timeline and
always behave as if 'latest' was specified.
---
doc/src/sgml/config.sgml | 15 ++++++++++++---
doc/src/sgml/high-availability.sgml | 8 ++------
src/backend/access/transam/xlog.c | 7 +++++++
src/bin/pg_rewind/RewindTest.pm | 2 --
src/test/recovery/t/004_timeline_switch.pl | 1 -
src/test/recovery/t/009_twophase.pl | 12 ------------
src/test/recovery/t/012_subtransactions.pl | 12 ------------
7 files changed, 21 insertions(+), 36 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index e94b305add..76a83246ee 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -3352,13 +3352,22 @@ <title>Recovery Target</title>
<para>
Specifies recovering into a particular timeline. The default is
to recover along the same timeline that was current when the
- base backup was taken. Setting this to <literal>latest</literal>
recovers
- to the latest timeline found in the archive, which is useful in
- a standby server. Other than that you only need to set this parameter
+ base backup was taken. Setting this to <literal>latest</literal>
recovers
+ to the latest timeline found in the archive.
+ </para>
+
+ <para>
+ You only need to set this parameter
in complex re-recovery situations, where you need to return to
a state that itself was reached after a point-in-time recovery.
See <xref linkend="backup-timelines"/> for discussion.
</para>
+
+ <para>
+ In standby mode, this parameter is ignored and the latest timeline is
+ always used. This allows a standby to follow timeline changes in
+ upstream servers.
+ </para>
</listitem>
</varlistentry>
diff --git a/doc/src/sgml/high-availability.sgml
b/doc/src/sgml/high-availability.sgml
index d8fd195da0..47a93aef5b 100644
--- a/doc/src/sgml/high-availability.sgml
+++ b/doc/src/sgml/high-availability.sgml
@@ -689,10 +689,7 @@ <title>Setting Up a Standby Server</title>
server (see <xref linkend="backup-pitr-recovery"/>). Create a file
<filename>standby.signal</filename> in the standby's cluster data
directory. Set <xref linkend="guc-restore-command"/> to a simple command
to copy files from
- the WAL archive. If you plan to have multiple standby servers for high
- availability purposes, set <varname>recovery_target_timeline</varname> to
- <literal>latest</literal>, to make the standby server follow the timeline
change
- that occurs at failover to another standby.
+ the WAL archive.
</para>
<note>
@@ -1023,8 +1020,7 @@ <title>Cascading Replication</title>
<para>
If an upstream standby server is promoted to become new master, downstream
- servers will continue to stream from the new master if
- <varname>recovery_target_timeline</varname> is set to
<literal>'latest'</literal>.
+ servers will continue to stream from the new master.
</para>
<para>
diff --git a/src/backend/access/transam/xlog.c
b/src/backend/access/transam/xlog.c
index 5729867879..315fff48c7 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5420,6 +5420,13 @@ validateRecoveryParameters(void)
!EnableHotStandby)
recoveryTargetAction = RECOVERY_TARGET_ACTION_SHUTDOWN;
+ /*
+ * In standby mode, always use latest timeline, ignoring
+ * recovery_target_timeline setting.
+ */
+ if (StandbyModeRequested)
+ recoveryTargetTimeLineGoal = RECOVERY_TARGET_TIMELINE_LATEST;
+
/*
* If user specified recovery_target_timeline, validate it or compute
the
* "latest" value. We can't do this until after we've gotten the
restore
diff --git a/src/bin/pg_rewind/RewindTest.pm b/src/bin/pg_rewind/RewindTest.pm
index 3d07da5d94..85cae7e47b 100644
--- a/src/bin/pg_rewind/RewindTest.pm
+++ b/src/bin/pg_rewind/RewindTest.pm
@@ -161,7 +161,6 @@ sub create_standby
$node_standby->append_conf(
"postgresql.conf", qq(
primary_conninfo='$connstr_master application_name=rewind_standby'
-recovery_target_timeline='latest'
));
$node_standby->set_standby_mode();
@@ -273,7 +272,6 @@ sub run_pg_rewind
$node_master->append_conf(
'postgresql.conf', qq(
primary_conninfo='port=$port_standby'
-recovery_target_timeline='latest'
));
$node_master->set_standby_mode();
diff --git a/src/test/recovery/t/004_timeline_switch.pl
b/src/test/recovery/t/004_timeline_switch.pl
index 79cbffb827..2b315854bc 100644
--- a/src/test/recovery/t/004_timeline_switch.pl
+++ b/src/test/recovery/t/004_timeline_switch.pl
@@ -51,7 +51,6 @@
$node_standby_2->append_conf(
'postgresql.conf', qq(
primary_conninfo='$connstr_1 application_name=@{[$node_standby_2->name]}'
-recovery_target_timeline='latest'
));
$node_standby_2->restart;
diff --git a/src/test/recovery/t/009_twophase.pl
b/src/test/recovery/t/009_twophase.pl
index dac2d4ec0d..2be1afcd8b 100644
--- a/src/test/recovery/t/009_twophase.pl
+++ b/src/test/recovery/t/009_twophase.pl
@@ -229,10 +229,6 @@ sub configure_and_reload
# restart old master as new standby
$cur_standby->enable_streaming($cur_master);
-$cur_standby->append_conf(
- 'postgresql.conf', qq(
-recovery_target_timeline='latest'
-));
$cur_standby->start;
###############################################################################
@@ -267,10 +263,6 @@ sub configure_and_reload
# restart old master as new standby
$cur_standby->enable_streaming($cur_master);
-$cur_standby->append_conf(
- 'postgresql.conf', qq(
-recovery_target_timeline='latest'
-));
$cur_standby->start;
$cur_master->psql('postgres', "COMMIT PREPARED 'xact_009_11'");
@@ -307,10 +299,6 @@ sub configure_and_reload
# restart old master as new standby
$cur_standby->enable_streaming($cur_master);
-$cur_standby->append_conf(
- 'postgresql.conf', qq(
-recovery_target_timeline='latest'
-));
$cur_standby->start;
$cur_master->psql('postgres', "COMMIT PREPARED 'xact_009_12'");
diff --git a/src/test/recovery/t/012_subtransactions.pl
b/src/test/recovery/t/012_subtransactions.pl
index e26cc9c2ce..c184553694 100644
--- a/src/test/recovery/t/012_subtransactions.pl
+++ b/src/test/recovery/t/012_subtransactions.pl
@@ -119,10 +119,6 @@
# restore state
($node_master, $node_standby) = ($node_standby, $node_master);
$node_standby->enable_streaming($node_master);
-$node_standby->append_conf(
- 'postgresql.conf', qq(
-recovery_target_timeline='latest'
-));
$node_standby->start;
$node_standby->psql(
'postgres',
@@ -170,10 +166,6 @@
# restore state
($node_master, $node_standby) = ($node_standby, $node_master);
$node_standby->enable_streaming($node_master);
-$node_standby->append_conf(
- 'postgresql.conf', qq(
-recovery_target_timeline='latest'
-));
$node_standby->start;
$psql_rc = $node_master->psql('postgres', "COMMIT PREPARED 'xact_012_1'");
is($psql_rc, '0',
@@ -211,10 +203,6 @@
# restore state
($node_master, $node_standby) = ($node_standby, $node_master);
$node_standby->enable_streaming($node_master);
-$node_standby->append_conf(
- 'postgresql.conf', qq(
-recovery_target_timeline='latest'
-));
$node_standby->start;
$psql_rc = $node_master->psql('postgres', "ROLLBACK PREPARED 'xact_012_1'");
is($psql_rc, '0',
--
2.20.1
