On Tue, Aug 23, 2016 at 12:49 AM, Robert Haas <robertmh...@gmail.com> wrote:
> On Mon, Aug 22, 2016 at 8:28 AM, Michael Paquier
> <michael.paqu...@gmail.com> wrote:
>> On Mon, Aug 22, 2016 at 7:12 PM, Adrien Nayrat <adrien.nay...@dalibo.com>
>> wrote:
>>> As Julien said, there is nothing to notice that error comes from
>>> recovery.conf.
>>> My fear would be that an user encounters an error like this. Il will be
>>> difficult to link to the recovery.conf.
>>
>> Thinking a bit wider than that, we may want to know such context for
>> normal GUC parameters as well, and that's not the case now. Perhaps
>> there is actually a reason why that's not done for GUCs, but it seems
>> that it would be useful there as well. That would give another reason
>> to move all that under the GUC umbrella.
>
> Maybe so, but that's been tried multiple times without success. If
> you think an error context is useful here, and I bet it is, I'd say
> just add it and be done with it.
This has finished by being less ugly than I thought, so I implemented
it as attached. Patch 0001 introduces recovery_target_lsn, and patch
0002 sets up an error context callback generating things like that on
failure:
FATAL: invalid input syntax for type pg_lsn: "popo"
CONTEXT: line 11 of configuration file "recovery.conf", parameter
"recovery_target_lsn"
--
Michael
From 6f73e9b02ee9806dd73571e1190983748fcad03d Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@otacoo.com>
Date: Tue, 23 Aug 2016 16:12:03 +0900
Subject: [PATCH 1/2] Introduce recovery_target_lsn in recovery.conf
This new recovery target can be used to stop recovery once a given WAL
position is reached (LSN). Tests and documentation are added.
---
doc/src/sgml/recovery-config.sgml | 24 +++++++--
src/backend/access/transam/recovery.conf.sample | 6 ++-
src/backend/access/transam/xlog.c | 69 +++++++++++++++++++++++++
src/include/access/xlog.h | 1 +
src/test/recovery/t/003_recovery_targets.pl | 28 ++++++++--
5 files changed, 119 insertions(+), 9 deletions(-)
diff --git a/doc/src/sgml/recovery-config.sgml
b/doc/src/sgml/recovery-config.sgml
index 26af221..ad977d3 100644
--- a/doc/src/sgml/recovery-config.sgml
+++ b/doc/src/sgml/recovery-config.sgml
@@ -157,9 +157,10 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'
# Windows
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 used; if more than one of these
- is specified in the configuration file, the last entry will be used.
+ <varname>recovery_target_lsn</>, <varname>recovery_target_name</>,
+ <varname>recovery_target_time</>, or <varname>recovery_target_xid</>
+ can be used; if more than one of these is specified in the configuration
+ file, the last entry will be used.
</para>
<variablelist>
@@ -232,6 +233,23 @@ 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">. This
+ parameter is parsed using the system data type
+ <link linkend="datatype-pg-lsn"><type>pg_lsn</></link>.
+ </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..7a16751 100644
--- a/src/backend/access/transam/recovery.conf.sample
+++ b/src/backend/access/transam/recovery.conf.sample
@@ -67,8 +67,8 @@
# 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
-# transaction(s) with the recovery target value (ie, stop either
+# by timestamp or by WAL position (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..e3985ee 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 +5081,23 @@ 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.
+ */
+ recoveryTargetLSN =
+ DatumGetLSN(DirectFunctionCall3(pg_lsn_in,
+
CStringGetDatum(item->value),
+
ObjectIdGetDatum(InvalidOid),
+
Int32GetDatum(-1)));
+ 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)
@@ -5388,11 +5408,29 @@ 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 WAL position
(LSN) \"%X/%X\"",
+ (uint32) (recoveryStopLSN >>
32),
+ (uint32) recoveryStopLSN)));
+ return true;
+ }
+
/* Otherwise we only consider stopping before COMMIT or ABORT records.
*/
if (XLogRecGetRmid(record) != RM_XACT_ID)
return false;
@@ -5467,6 +5505,7 @@ recoveryStopsBefore(XLogReaderState *record)
recoveryStopAfter = false;
recoveryStopXid = recordXid;
recoveryStopTime = recordXtime;
+ recoveryStopLSN = InvalidXLogRecPtr;
recoveryStopName[0] = '\0';
if (isCommit)
@@ -5520,6 +5559,7 @@ recoveryStopsAfter(XLogReaderState *record)
{
recoveryStopAfter = true;
recoveryStopXid = InvalidTransactionId;
+ recoveryStopLSN = InvalidXLogRecPtr;
(void) getRecordTimestamp(record, &recoveryStopTime);
strlcpy(recoveryStopName,
recordRestorePointData->rp_name, MAXFNAMELEN);
@@ -5531,6 +5571,23 @@ 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 WAL position
(LSN) \"%X/%X\"",
+ (uint32) (recoveryStopLSN >>
32),
+ (uint32) recoveryStopLSN)));
+ return true;
+ }
+
if (rmid != RM_XACT_ID)
return false;
@@ -5586,6 +5643,7 @@ recoveryStopsAfter(XLogReaderState *record)
recoveryStopAfter = true;
recoveryStopXid = recordXid;
recoveryStopTime = recordXtime;
+ recoveryStopLSN = InvalidXLogRecPtr;
recoveryStopName[0] = '\0';
if (xact_info == XLOG_XACT_COMMIT ||
@@ -5617,6 +5675,7 @@ recoveryStopsAfter(XLogReaderState *record)
recoveryStopAfter = true;
recoveryStopXid = InvalidTransactionId;
recoveryStopTime = 0;
+ recoveryStopLSN = InvalidXLogRecPtr;
recoveryStopName[0] = '\0';
return true;
}
@@ -6043,6 +6102,11 @@ 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 WAL position (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 +7176,11 @@ 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);
--
2.9.3
From 82a591ca8be457f8be4f13080ededc5daabf3670 Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@otacoo.com>
Date: Tue, 23 Aug 2016 16:28:05 +0900
Subject: [PATCH 2/2] Introduce error callback when parsing recovery.conf
At the moment an error occurs when recovery.conf is parsed, generate
a context message related to the parameter used, as follows:
CONTEXT: line 11 of configuration file "recovery.conf", parameter foo
This is useful to understand from where a parsing failure is coming in
recovery.conf, particularly for parameters like recovery_target_time and
recovery_target_lsn that do not have recovery-specific error messages.
---
src/backend/access/transam/xlog.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/src/backend/access/transam/xlog.c
b/src/backend/access/transam/xlog.c
index e3985ee..9097841 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -4935,6 +4935,20 @@ str_time(pg_time_t tnow)
}
/*
+ * error context callback for parsing of recovery.conf
+ *
+ * The argument for the error context must be of type ConfigVariable.
+ */
+static void
+readRecoveryErrorCallback(void *arg)
+{
+ ConfigVariable *item = (ConfigVariable *) arg;
+
+ errcontext("line %d of configuration file \"%s\", parameter \"%s\"",
+ item->sourceline, item->filename, item->name);
+}
+
+/*
* See if there is a recovery command file (recovery.conf), and if so
* read in parameters for archive recovery and XLOG streaming.
*
@@ -4950,6 +4964,7 @@ readRecoveryCommandFile(void)
*head = NULL,
*tail = NULL;
bool recoveryTargetActionSet = false;
+ ErrorContextCallback errcallback;
fd = AllocateFile(RECOVERY_COMMAND_FILE, "r");
@@ -4971,8 +4986,15 @@ readRecoveryCommandFile(void)
FreeFile(fd);
+ /* set up callback to identify file parsing information on failure */
+ errcallback.callback = readRecoveryErrorCallback;
+ errcallback.previous = error_context_stack;
+ error_context_stack = &errcallback;
+
for (item = head; item; item = item->next)
{
+ errcallback.arg = (void *) item;
+
if (strcmp(item->name, "restore_command") == 0)
{
recoveryRestoreCommand = pstrdup(item->value);
@@ -5179,6 +5201,9 @@ readRecoveryCommandFile(void)
item->name)));
}
+ /* Done, clean up */
+ error_context_stack = errcallback.previous;
+
/*
* Check for compulsory parameters
*/
--
2.9.3
--
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