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action_at_recovery_target recovery config option

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action_at_recovery_target = pause | promote | shutdown

Petr Jelinek

Reviewed by Muhammad Asif Naeem, Fujji Masao and
Simon Riggs
This commit is contained in:
Simon Riggs 2014-11-25 20:13:30 +00:00
parent bb1b8f694a
commit aedccb1f6f
4 changed files with 159 additions and 19 deletions
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58
doc/src/sgml/recovery-config.sgml
View File

@ -289,12 +289,39 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</term>
<listitem>
<para>
Specifies whether recovery should pause when the recovery target
is reached. The default is true.
This is intended to allow queries to be executed against the
database to check if this recovery target is the most desirable
point for recovery. The paused state can be resumed by using
<function>pg_xlog_replay_resume()</> (See
Alias for action_at_recovery_target, <literal>true</> is same as
action_at_recovery_target = <literal>pause</> and <literal>false</>
is same as action_at_recovery_target = <literal>promote</>.
</para>
<para>
This setting has no effect if <xref linkend="guc-hot-standby"> is not
enabled, or if no recovery target is set.
</para>
</listitem>
</varlistentry>
</variablelist>
<varlistentry id="action-at-recovery-target"
xreflabel="action_at_recovery_target">
<term><varname>action_at_recovery_target</varname> (<type>enum</type>)
<indexterm>
<primary><varname>action_at_recovery_target</> recovery parameter</primary>
</indexterm>
</term>
<listitem>
<para>
Specifies what action the server should take once the recovery target is
reached. The default is <literal>pause</>, which means recovery will
be paused. <literal>promote</> means recovery process will finish and
the server will start to accept connections.
Finally <literal>shutdown</> will stop the server after reaching the
recovery target.
</para>
The intended use of <literal>pause</> setting is to allow queries to be
executed against the database to check if this recovery target is the
most desirable point for recovery. The paused state can be resumed by
using <function>pg_xlog_replay_resume()</> (See
<xref linkend="functions-recovery-control-table">), which then
causes recovery to end. If this recovery target is not the
desired stopping point, then shutdown the server, change the
@ -302,8 +329,23 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
continue recovery.
</para>
<para>
This setting has no effect if <xref linkend="guc-hot-standby"> is not
enabled, or if no recovery target is set.
The <literal>shutdown</> setting is useful to have instance ready at
exact replay point desired.
The instance will still be able to replay more WAL records (and in fact
will have to replay WAL records since last checkpoint next time it is
started).
</para>
<para>
Note that because <filename>recovery.conf</> will not be renamed when
<varname>action_at_recovery_target</> is set to <literal>shutdown</>,
any subsequent start will end with immediate shutdown unless the
configuration is changed or the <filename>recovery.conf</> is removed
manually.
</para>
<para>
This setting has no effect if no recovery target is set.
If <xref linkend="guc-hot-standby"> is not enabled, a setting of
<literal>pause</> will act the same as <literal>shutdown</>.
</para>
</listitem>
</varlistentry>

98
src/backend/access/transam/xlog.c
View File

@ -228,7 +228,7 @@ static char *recoveryEndCommand = NULL;
static char *archiveCleanupCommand = NULL;
static RecoveryTargetType recoveryTarget = RECOVERY_TARGET_UNSET;
static bool recoveryTargetInclusive = true;
static bool recoveryPauseAtTarget = true;
static RecoveryTargetAction actionAtRecoveryTarget = RECOVERY_TARGET_ACTION_PAUSE;
static TransactionId recoveryTargetXid;
static TimestampTz recoveryTargetTime;
static char *recoveryTargetName;
@ -4647,6 +4647,9 @@ readRecoveryCommandFile(void)
ConfigVariable *item,
*head = NULL,
*tail = NULL;
bool recoveryPauseAtTargetSet = false;
bool actionAtRecoveryTargetSet = false;
fd = AllocateFile(RECOVERY_COMMAND_FILE, "r");
if (fd == NULL)
@ -4692,13 +4695,43 @@ readRecoveryCommandFile(void)
}
else if (strcmp(item->name, "pause_at_recovery_target") == 0)
{
bool recoveryPauseAtTarget;
if (!parse_bool(item->value, &recoveryPauseAtTarget))
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("parameter \"%s\" requires a Boolean value", "pause_at_recovery_target")));
ereport(DEBUG2,
(errmsg_internal("pause_at_recovery_target = '%s'",
item->value)));
actionAtRecoveryTarget = recoveryPauseAtTarget ?
RECOVERY_TARGET_ACTION_PAUSE :
RECOVERY_TARGET_ACTION_PROMOTE;
recoveryPauseAtTargetSet = true;
}
else if (strcmp(item->name, "action_at_recovery_target") == 0)
{
if (strcmp(item->value, "pause") == 0)
actionAtRecoveryTarget = RECOVERY_TARGET_ACTION_PAUSE;
else if (strcmp(item->value, "promote") == 0)
actionAtRecoveryTarget = RECOVERY_TARGET_ACTION_PROMOTE;
else if (strcmp(item->value, "shutdown") == 0)
actionAtRecoveryTarget = RECOVERY_TARGET_ACTION_SHUTDOWN;
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid value for recovery parameter \"%s\"",
"action_at_recovery_target"),
errhint("The allowed values are \"pause\", \"promote\" and \"shutdown\".")));
ereport(DEBUG2,
(errmsg_internal("action_at_recovery_target = '%s'",
item->value)));
actionAtRecoveryTargetSet = true;
}
else if (strcmp(item->name, "recovery_target_timeline") == 0)
{
@ -4863,6 +4896,28 @@ readRecoveryCommandFile(void)
RECOVERY_COMMAND_FILE)));
}
/*
* Check for mutually exclusive parameters
*/
if (recoveryPauseAtTargetSet && actionAtRecoveryTargetSet)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("cannot set both \"%s\" and \"%s\" recovery parameters",
"pause_at_recovery_target",
"action_at_recovery_target"),
errhint("The \"pause_at_recovery_target\" is deprecated.")));
/*
* Override any inconsistent requests. Not that this is a change
* of behaviour in 9.5; prior to this we simply ignored a request
* to pause if hot_standby = off, which was surprising behaviour.
*/
if (actionAtRecoveryTarget == RECOVERY_TARGET_ACTION_PAUSE &&
actionAtRecoveryTargetSet &&
standbyState == STANDBY_DISABLED)
actionAtRecoveryTarget = RECOVERY_TARGET_ACTION_SHUTDOWN;
/* Enable fetching from archive recovery area */
ArchiveRecoveryRequested = true;
@ -6415,10 +6470,37 @@ StartupXLOG(void)
* end of main redo apply loop
*/
if (recoveryPauseAtTarget && reachedStopPoint)
if (reachedStopPoint)
{
SetRecoveryPause(true);
recoveryPausesHere();
if (!reachedConsistency)
ereport(FATAL,
(errmsg("requested recovery stop point is before consistent recovery point")));
/*
* This is the last point where we can restart recovery with a
* new recovery target, if we shutdown and begin again. After
* this, Resource Managers may choose to do permanent corrective
* actions at end of recovery.
*/
switch (actionAtRecoveryTarget)
{
case RECOVERY_TARGET_ACTION_SHUTDOWN:
/*
* exit with special return code to request shutdown
* of postmaster. Log messages issued from
* postmaster.
*/
proc_exit(3);
case RECOVERY_TARGET_ACTION_PAUSE:
SetRecoveryPause(true);
recoveryPausesHere();
/* drop into promote */
case RECOVERY_TARGET_ACTION_PROMOTE:
break;
}
}
/* Allow resource managers to do any required cleanup. */
@ -6436,6 +6518,7 @@ StartupXLOG(void)
ereport(LOG,
(errmsg("last completed transaction was at log time %s",
timestamptz_to_str(xtime))));
InRedo = false;
}
else
@ -6496,13 +6579,6 @@ StartupXLOG(void)
(EndOfLog < minRecoveryPoint ||
!XLogRecPtrIsInvalid(ControlFile->backupStartPoint)))
{
if (reachedStopPoint)
{
/* stopped because of stop request */
ereport(FATAL,
(errmsg("requested recovery stop point is before consistent recovery point")));
}
/*
* Ran off end of WAL before reaching end-of-backup WAL record, or
* minRecoveryPoint. That's usually a bad sign, indicating that you

12
src/backend/postmaster/postmaster.c
View File

@ -509,6 +509,7 @@ static void ShmemBackendArrayRemove(Backend *bn);
/* Macros to check exit status of a child process */
#define EXIT_STATUS_0(st) ((st) == 0)
#define EXIT_STATUS_1(st) (WIFEXITED(st) && WEXITSTATUS(st) == 1)
#define EXIT_STATUS_3(st) (WIFEXITED(st) && WEXITSTATUS(st) == 3)
#ifndef WIN32
/*
@ -2555,6 +2556,17 @@ reaper(SIGNAL_ARGS)
continue;
}
if (EXIT_STATUS_3(exitstatus))
{
ereport(LOG,
(errmsg("shutdown at recovery target")));
Shutdown = SmartShutdown;
TerminateChildren(SIGTERM);
pmState = PM_WAIT_BACKENDS;
/* PostmasterStateMachine logic does the rest */
continue;
}
/*
* Unexpected exit of startup process (including FATAL exit)
* during PM_STARTUP is treated as catastrophic. There are no

10
src/include/access/xlog_internal.h
View File

@ -214,6 +214,16 @@ typedef struct XLogRecData
uint32 len; /* length of rmgr data to include */
} XLogRecData;
/*
* Recovery target action.
*/
typedef enum
{
RECOVERY_TARGET_ACTION_PAUSE,
RECOVERY_TARGET_ACTION_PROMOTE,
RECOVERY_TARGET_ACTION_SHUTDOWN,
} RecoveryTargetAction;
/*
* Method table for resource managers.
*