On 06/09/2016 02:33 PM, Michael Paquier wrote:
> On Wed, May 25, 2016 at 1:32 AM, Michael Paquier
> <[email protected]> wrote:
>> On Tue, May 24, 2016 at 9:29 AM, Alvaro Herrera
>> <[email protected]> wrote:
>>> Christoph Berg wrote:
>>>> Re: Michael Paquier 2016-05-24
>>>> <CAB7nPqQRXsC8=ozh6GpjLnpZ=meoouzoaabzx28n2bjsmv2...@mail.gmail.com>
>>>>> Yeah, that's really something that covers only a narrow case, though
>>>>> if we don't have it when we need it we're limited to some hacks.
>>>>> Perhaps people who have the advanced level to use such a thing have
>>>>> the level to use hacks anyway..
>>>>
>>>> I'd think recovery_target_lsn would be more useful in practice than
>>>> the existing recovery_target_xid. So I don't see why it shouldn't just
>>>> be added, also given it's likely very unobtrusive to do so.
>>>
>>> Also, see
>>> http://www.postgresql.org/message-id/[email protected]
>>
>> Looking at xlog.c it is not that complicated, and we could add tests
>> in 003_recovery_targets.pl at the same time. Perhaps somebody looking
>> for a first participation would be interested in this small project?
>
> Oh, well. I have implemented it as attached by introducing
> recovery_target_lsn as a new recovery parameter. This takes into
> account recovery_target_inclusive and stops at the precise point of a
> record without being influenced by the xact records, in a way similar
> recovery_target_name. Tests and documentation are added, and this is
> part of the next CF.
>
>
>
>
Hi,
I reviewed this patch rebased to deal with
f6ced51f9188ad5806219471a0b40a91dde923aa, and minor adjustment (see below)
It do the job. However if you use an incorrect recovery_target_lsn you
get this message :
"FATAL: invalid input syntax for type pg_lsn: "0RT5/4""
I added a PG_TRY/PG_CATCH section in order to get a more explicit message :
FATAL: wrong recovery_target_lsn (must be pg_lsn type)
I am not sure if it is the best solution?
Thanks to Julien Rouhaud for his help.
--
Adrien NAYRAT
http://dalibo.com - http://dalibo.org
diff --git a/doc/src/sgml/recovery-config.sgml b/doc/src/sgml/recovery-config.sgml
index 26af221..e131b7d 100644
--- a/doc/src/sgml/recovery-config.sgml
+++ b/doc/src/sgml/recovery-config.sgml
@@ -232,6 +232,21 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</para>
</listitem>
</varlistentry>
+
+ <varlistentry id="recovery-target-lsn" xreflabel="recovery_target_lsn">
+ <term><varname>recovery_target_lsn</varname> (<type>pg_lsn</type>)
+ <indexterm>
+ <primary><varname>recovery_target_lsn</> recovery parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ This parameter specifies the LSN of the write-ahead log stream up to
+ which recovery will proceed. The precise stopping point is also
+ influenced by <xref linkend="recovery-target-inclusive">.
+ </para>
+ </listitem>
+ </varlistentry>
</variablelist>
<para>
diff --git a/src/backend/access/transam/recovery.conf.sample b/src/backend/access/transam/recovery.conf.sample
index b777400..32f6903 100644
--- a/src/backend/access/transam/recovery.conf.sample
+++ b/src/backend/access/transam/recovery.conf.sample
@@ -67,7 +67,7 @@
# must set a recovery target.
#
# You may set a recovery target either by transactionId, by name,
-# or by timestamp. Recovery may either include or exclude the
+# by timestamp or by LSN. Recovery may either include or exclude the
# transaction(s) with the recovery target value (ie, stop either
# just after or just before the given target, respectively).
#
@@ -78,6 +78,8 @@
#
#recovery_target_xid = ''
#
+#recovery_target_lsn = '' # e.g. '0/70006B8'
+#
#recovery_target_inclusive = true
#
#
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index f13f9c1..762c7bb 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -67,6 +67,7 @@
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/memutils.h"
+#include "utils/pg_lsn.h"
#include "utils/ps_status.h"
#include "utils/relmapper.h"
#include "utils/snapmgr.h"
@@ -254,6 +255,7 @@ static RecoveryTargetAction recoveryTargetAction = RECOVERY_TARGET_ACTION_PAUSE;
static TransactionId recoveryTargetXid;
static TimestampTz recoveryTargetTime;
static char *recoveryTargetName;
+static XLogRecPtr recoveryTargetLSN;
static int recovery_min_apply_delay = 0;
static TimestampTz recoveryDelayUntilTime;
@@ -275,6 +277,7 @@ static bool fast_promote = false;
*/
static TransactionId recoveryStopXid;
static TimestampTz recoveryStopTime;
+static XLogRecPtr recoveryStopLSN;
static char recoveryStopName[MAXFNAMELEN];
static bool recoveryStopAfter;
@@ -5078,6 +5081,34 @@ readRecoveryCommandFile(void)
(errmsg_internal("recovery_target_name = '%s'",
recoveryTargetName)));
}
+ else if (strcmp(item->name, "recovery_target_lsn") == 0)
+ {
+ recoveryTarget = RECOVERY_TARGET_LSN;
+
+ /*
+ * Convert the LSN string given by the user to XLogRecPtr form.
+ */
+ PG_TRY();
+ {
+ recoveryTargetLSN =
+ DatumGetLSN(DirectFunctionCall3(pg_lsn_in,
+ CStringGetDatum(item->value),
+ ObjectIdGetDatum(InvalidOid),
+ Int32GetDatum(-1)));
+ }
+ PG_CATCH();
+ {
+ ereport(FATAL,
+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+ errmsg("wrong recovery_target_lsn (must be pg_lsn type)",
+ MAXFNAMELEN - 1)));
+ }
+ PG_END_TRY();
+ ereport(DEBUG2,
+ (errmsg_internal("recovery_target_lsn = '%X/%X'",
+ (uint32) (recoveryTargetLSN >> 32),
+ (uint32) recoveryTargetLSN)));
+ }
else if (strcmp(item->name, "recovery_target") == 0)
{
if (strcmp(item->value, "immediate") == 0)
@@ -5388,8 +5419,26 @@ recoveryStopsBefore(XLogReaderState *record)
recoveryStopAfter = false;
recoveryStopXid = InvalidTransactionId;
+ recoveryStopLSN = InvalidXLogRecPtr;
+ recoveryStopTime = 0;
+ recoveryStopName[0] = '\0';
+ return true;
+ }
+
+ /* Check if target LSN has been reached */
+ if (recoveryTarget == RECOVERY_TARGET_LSN &&
+ !recoveryTargetInclusive &&
+ record->ReadRecPtr >= recoveryTargetLSN)
+ {
+ recoveryStopAfter = false;
+ recoveryStopXid = InvalidTransactionId;
+ recoveryStopLSN = record->ReadRecPtr;
recoveryStopTime = 0;
recoveryStopName[0] = '\0';
+ ereport(LOG,
+ (errmsg("recovery stopping before LSN \"%X/%X\"",
+ (uint32) (recoveryStopLSN >> 32),
+ (uint32) recoveryStopLSN)));
return true;
}
@@ -5467,6 +5516,7 @@ recoveryStopsBefore(XLogReaderState *record)
recoveryStopAfter = false;
recoveryStopXid = recordXid;
recoveryStopTime = recordXtime;
+ recoveryStopLSN = InvalidXLogRecPtr;
recoveryStopName[0] = '\0';
if (isCommit)
@@ -5520,6 +5570,7 @@ recoveryStopsAfter(XLogReaderState *record)
{
recoveryStopAfter = true;
recoveryStopXid = InvalidTransactionId;
+ recoveryStopLSN = InvalidXLogRecPtr;
(void) getRecordTimestamp(record, &recoveryStopTime);
strlcpy(recoveryStopName, recordRestorePointData->rp_name, MAXFNAMELEN);
@@ -5531,6 +5582,23 @@ recoveryStopsAfter(XLogReaderState *record)
}
}
+ /* Check if the target LSN has been reached */
+ if (recoveryTarget == RECOVERY_TARGET_LSN &&
+ recoveryTargetInclusive &&
+ record->ReadRecPtr >= recoveryTargetLSN)
+ {
+ recoveryStopAfter = true;
+ recoveryStopXid = InvalidTransactionId;
+ recoveryStopLSN = record->ReadRecPtr;
+ recoveryStopTime = 0;
+ recoveryStopName[0] = '\0';
+ ereport(LOG,
+ (errmsg("recovery stopping after LSN \"%X/%X\"",
+ (uint32) (recoveryStopLSN >> 32),
+ (uint32) recoveryStopLSN)));
+ return true;
+ }
+
if (rmid != RM_XACT_ID)
return false;
@@ -5586,6 +5654,7 @@ recoveryStopsAfter(XLogReaderState *record)
recoveryStopAfter = true;
recoveryStopXid = recordXid;
recoveryStopTime = recordXtime;
+ recoveryStopLSN = InvalidXLogRecPtr;
recoveryStopName[0] = '\0';
if (xact_info == XLOG_XACT_COMMIT ||
@@ -5617,6 +5686,7 @@ recoveryStopsAfter(XLogReaderState *record)
recoveryStopAfter = true;
recoveryStopXid = InvalidTransactionId;
recoveryStopTime = 0;
+ recoveryStopLSN = InvalidXLogRecPtr;
recoveryStopName[0] = '\0';
return true;
}
@@ -6043,6 +6113,11 @@ StartupXLOG(void)
ereport(LOG,
(errmsg("starting point-in-time recovery to \"%s\"",
recoveryTargetName)));
+ else if (recoveryTarget == RECOVERY_TARGET_LSN)
+ ereport(LOG,
+ (errmsg("starting point-in-time recovery to LSN \"%X/%X\"",
+ (uint32) (recoveryTargetLSN >> 32),
+ (uint32) recoveryTargetLSN)));
else if (recoveryTarget == RECOVERY_TARGET_IMMEDIATE)
ereport(LOG,
(errmsg("starting point-in-time recovery to earliest consistent point")));
@@ -7112,6 +7187,11 @@ StartupXLOG(void)
"%s %s\n",
recoveryStopAfter ? "after" : "before",
timestamptz_to_str(recoveryStopTime));
+ else if (recoveryTarget == RECOVERY_TARGET_LSN)
+ snprintf(reason, sizeof(reason),
+ "at LSN %X/%X\n",
+ (uint32 ) (recoveryStopLSN >> 32),
+ (uint32) recoveryStopLSN);
else if (recoveryTarget == RECOVERY_TARGET_NAME)
snprintf(reason, sizeof(reason),
"at restore point \"%s\"",
diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index 14b7f7f..c9f332c 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -83,6 +83,7 @@ typedef enum
RECOVERY_TARGET_XID,
RECOVERY_TARGET_TIME,
RECOVERY_TARGET_NAME,
+ RECOVERY_TARGET_LSN,
RECOVERY_TARGET_IMMEDIATE
} RecoveryTargetType;
diff --git a/src/test/recovery/t/003_recovery_targets.pl b/src/test/recovery/t/003_recovery_targets.pl
index d1f6d78..a82545b 100644
--- a/src/test/recovery/t/003_recovery_targets.pl
+++ b/src/test/recovery/t/003_recovery_targets.pl
@@ -3,7 +3,7 @@ use strict;
use warnings;
use PostgresNode;
use TestLib;
-use Test::More tests => 7;
+use Test::More tests => 9;
# Create and test a standby from given backup, with a certain
# recovery target.
@@ -86,6 +86,16 @@ my $lsn4 =
$node_master->safe_psql('postgres',
"SELECT pg_create_restore_point('$recovery_name');");
+# And now for a recovery target LSN
+$node_master->safe_psql('postgres',
+ "INSERT INTO tab_int VALUES (generate_series(4001,5000))");
+my $recovery_lsn = $node_master->safe_psql('postgres', "SELECT pg_current_xlog_location()");
+my $lsn5 =
+ $node_master->safe_psql('postgres', "SELECT pg_current_xlog_location();");
+
+$node_master->safe_psql('postgres',
+ "INSERT INTO tab_int VALUES (generate_series(5001,6000))");
+
# Force archiving of WAL file
$node_master->safe_psql('postgres', "SELECT pg_switch_xlog()");
@@ -102,6 +112,9 @@ test_recovery_standby('time', 'standby_3', $node_master, \@recovery_params,
@recovery_params = ("recovery_target_name = '$recovery_name'");
test_recovery_standby('name', 'standby_4', $node_master, \@recovery_params,
"4000", $lsn4);
+@recovery_params = ("recovery_target_lsn = '$recovery_lsn'");
+test_recovery_standby('LSN', 'standby_5', $node_master, \@recovery_params,
+ "5000", $lsn5);
# Multiple targets
# Last entry has priority (note that an array respects the order of items
@@ -111,16 +124,23 @@ test_recovery_standby('name', 'standby_4', $node_master, \@recovery_params,
"recovery_target_xid = '$recovery_txid'",
"recovery_target_time = '$recovery_time'");
test_recovery_standby('name + XID + time',
- 'standby_5', $node_master, \@recovery_params, "3000", $lsn3);
+ 'standby_6', $node_master, \@recovery_params, "3000", $lsn3);
@recovery_params = (
"recovery_target_time = '$recovery_time'",
"recovery_target_name = '$recovery_name'",
"recovery_target_xid = '$recovery_txid'");
test_recovery_standby('time + name + XID',
- 'standby_6', $node_master, \@recovery_params, "2000", $lsn2);
+ 'standby_7', $node_master, \@recovery_params, "2000", $lsn2);
@recovery_params = (
"recovery_target_xid = '$recovery_txid'",
"recovery_target_time = '$recovery_time'",
"recovery_target_name = '$recovery_name'");
test_recovery_standby('XID + time + name',
- 'standby_7', $node_master, \@recovery_params, "4000", $lsn4);
+ 'standby_8', $node_master, \@recovery_params, "4000", $lsn4);
+@recovery_params = (
+ "recovery_target_xid = '$recovery_txid'",
+ "recovery_target_time = '$recovery_time'",
+ "recovery_target_name = '$recovery_name'",
+ "recovery_target_lsn = '$recovery_lsn'",);
+test_recovery_standby('XID + time + name + LSN',
+ 'standby_9', $node_master, \@recovery_params, "5000", $lsn5);
--
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