From 71c6a8e375b138af8aa46d80226ea9e98f2b94bc Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Sat, 25 Jan 2014 17:34:04 +0200
Subject: [PATCH] Add recovery_target='immediate' option.
This allows ending recovery as a consistent state has been reached. Without
this, there was no easy way to e.g restore an online backup, without
replaying any extra WAL after the backup ended.
MauMau and me.
---
doc/src/sgml/backup.sgml | 2 +-
doc/src/sgml/recovery-config.sgml | 44 +++++++++++++-----
.../access/transam/recovery.conf.sample | 6 +++
src/backend/access/transam/xlog.c | 46 ++++++++++++++++++-
src/include/access/xlog.h | 3 +-
5 files changed, 86 insertions(+), 15 deletions(-)
diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgml
index a2361d780fb..854b5fde41c 100644
--- a/doc/src/sgml/backup.sgml
+++ b/doc/src/sgml/backup.sgml
@@ -1124,7 +1124,7 @@ restore_command = 'cp /mnt/server/archivedir/%f %p'
<para>
If you want to recover to some previous point in time (say, right before
the junior DBA dropped your main transaction table), just specify the
- required stopping point in <filename>recovery.conf</>. You can specify
+ required <link linkend="recovery-target-settings">stopping point</link> in <filename>recovery.conf</>. You can specify
the stop point, known as the <quote>recovery target</>, either by
date/time, named restore point or by completion of a specific transaction
ID. As of this writing only the date/time and named restore point options
diff --git a/doc/src/sgml/recovery-config.sgml b/doc/src/sgml/recovery-config.sgml
index 550cdce6f99..b818197299d 100644
--- a/doc/src/sgml/recovery-config.sgml
+++ b/doc/src/sgml/recovery-config.sgml
@@ -199,8 +199,33 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
<sect1 id="recovery-target-settings">
<title>Recovery Target Settings</title>
+ <para>
+ By default, recovery will recover to the end of the WAL log. The
+ following parameters can be used to specify an earlier stopping point.
+ At most one of <varname>recovery_target</>,
+ <varname>recovery_target_name</>, <varname>recovery_target_time</>, or
+ <varname>recovery_target_xid</> can be specified.
+ </para>
<variablelist>
+ <varlistentry id="recovery-target" xreflabel="recovery_target_name">
+ <term><varname>recovery_target</varname><literal> = 'immediate'</literal></term>
+ <indexterm>
+ <primary><varname>recovery_target</> recovery parameter</primary>
+ </indexterm>
+ <listitem>
+ <para>
+ This parameter specifies that recovery should end as soon as a
+ consistency is reached, ie. as early as possible. When restoring from an
+ online backup, this means the point where taking the backup ended.
+ </para>
+ <para>
+ Technically, this is a string parameter, but <literal>'immediate'</>
+ is currently the only allowed value.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="recovery-target-name" xreflabel="recovery_target_name">
<term><varname>recovery_target_name</varname>
(<type>string</type>)
@@ -212,10 +237,6 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
<para>
This parameter specifies the named restore point, created with
<function>pg_create_restore_point()</> to which recovery will proceed.
- At most one of <varname>recovery_target_name</>,
- <xref linkend="recovery-target-time"> or
- <xref linkend="recovery-target-xid"> can be specified. The default is to
- recover to the end of the WAL log.
</para>
</listitem>
</varlistentry>
@@ -231,10 +252,6 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
<para>
This parameter specifies the time stamp up to which recovery
will proceed.
- At most one of <varname>recovery_target_time</>,
- <xref linkend="recovery-target-name"> or
- <xref linkend="recovery-target-xid"> can be specified.
- The default is to recover to the end of the WAL log.
The precise stopping point is also influenced by
<xref linkend="recovery-target-inclusive">.
</para>
@@ -254,15 +271,18 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
start, transactions can complete in a different numeric order.
The transactions that will be recovered are those that committed
before (and optionally including) the specified one.
- At most one of <varname>recovery_target_xid</>,
- <xref linkend="recovery-target-name"> or
- <xref linkend="recovery-target-time"> can be specified.
- The default is to recover to the end of the WAL log.
The precise stopping point is also influenced by
<xref linkend="recovery-target-inclusive">.
</para>
</listitem>
</varlistentry>
+ </variablelist>
+ <para>
+ The following options further specify the recovery target, and affect
+ what happens when the target is reached:
+ </para>
+
+ <variablelist>
<varlistentry id="recovery-target-inclusive"
xreflabel="recovery_target_inclusive">
diff --git a/src/backend/access/transam/recovery.conf.sample b/src/backend/access/transam/recovery.conf.sample
index 673605cfc66..6f7b38eb197 100644
--- a/src/backend/access/transam/recovery.conf.sample
+++ b/src/backend/access/transam/recovery.conf.sample
@@ -81,6 +81,12 @@
#recovery_target_inclusive = true
#
#
+# Alternatively, you can request stopping as soon as a consistent state
+# is reached, by uncommenting this option.
+#
+#recovery_target = 'immediate'
+#
+#
# If you want to recover into a timeline other than the "main line" shown in
# pg_control, specify the timeline number here, or write 'latest' to get
# the latest branch for which there's a history file.
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 9559d6d6aef..b333d820c72 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5434,6 +5434,19 @@ readRecoveryCommandFile(void)
(errmsg_internal("recovery_target_name = '%s'",
recoveryTargetName)));
}
+ else if (strcmp(item->name, "recovery_target") == 0)
+ {
+ if (strcmp(item->value, "immediate") == 0)
+ recoveryTarget = RECOVERY_TARGET_IMMEDIATE;
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("invalid recovery_target parameter"),
+ errhint("The only allowed value is 'immediate'")));
+ ereport(DEBUG2,
+ (errmsg_internal("recovery_target = '%s'",
+ item->value)));
+ }
else if (strcmp(item->name, "recovery_target_inclusive") == 0)
{
/*
@@ -5676,7 +5689,20 @@ recoveryStopsBefore(XLogRecord *record)
bool isCommit;
TimestampTz recordXtime = 0;
- /* We only consider stopping before COMMIT or ABORT records. */
+ /* Check if we should stop as soon as reaching consistency */
+ if (recoveryTarget == RECOVERY_TARGET_IMMEDIATE && reachedConsistency)
+ {
+ ereport(LOG,
+ (errmsg("recovery stopping after reaching consistency")));
+
+ recoveryStopAfter = false;
+ recoveryStopXid = InvalidTransactionId;
+ recoveryStopTime = 0;
+ recoveryStopName[0] = '\0';
+ return true;
+ }
+
+ /* Otherwise we only consider stopping before COMMIT or ABORT records. */
if (record->xl_rmid != RM_XACT_ID)
return false;
record_info = record->xl_info & ~XLR_INFO_MASK;
@@ -5825,6 +5851,19 @@ recoveryStopsAfter(XLogRecord *record)
}
}
+ /* Check if we should stop as soon as reaching consistency */
+ if (recoveryTarget == RECOVERY_TARGET_IMMEDIATE && reachedConsistency)
+ {
+ ereport(LOG,
+ (errmsg("recovery stopping after reaching consistency")));
+
+ recoveryStopAfter = true;
+ recoveryStopXid = InvalidTransactionId;
+ recoveryStopTime = 0;
+ recoveryStopName[0] = '\0';
+ return true;
+ }
+
return false;
}
@@ -6246,6 +6285,9 @@ StartupXLOG(void)
ereport(LOG,
(errmsg("starting point-in-time recovery to \"%s\"",
recoveryTargetName)));
+ else if (recoveryTarget == RECOVERY_TARGET_IMMEDIATE)
+ ereport(LOG,
+ (errmsg("starting point-in-time recovery to earliest consistent point")));
else
ereport(LOG,
(errmsg("starting archive recovery")));
@@ -7125,6 +7167,8 @@ StartupXLOG(void)
snprintf(reason, sizeof(reason),
"at restore point \"%s\"",
recoveryStopName);
+ else if (recoveryTarget == RECOVERY_TARGET_IMMEDIATE)
+ snprintf(reason, sizeof(reason), "reached consistency");
else
snprintf(reason, sizeof(reason), "no recovery target specified");
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 281f51629e4..47e302276b4 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -173,7 +173,8 @@ typedef enum
RECOVERY_TARGET_UNSET,
RECOVERY_TARGET_XID,
RECOVERY_TARGET_TIME,
- RECOVERY_TARGET_NAME
+ RECOVERY_TARGET_NAME,
+ RECOVERY_TARGET_IMMEDIATE
} RecoveryTargetType;
extern XLogRecPtr XactLastRecEnd;
--
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