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Commit959ac58

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In HS, Startup process sets SIGALRM when waiting for buffer pin. If
woken by alarm we send SIGUSR1 to all backends requesting that theycheck to see if they are blocking Startup process. If so, they throwERROR/FATAL as for other conflict resolutions. Deadlock stop gapremoved. max_standby_delay = -1 option removed to prevent deadlock.
1 parent4fa69e5 commit959ac58

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16 files changed

+367
-87
lines changed

16 files changed

+367
-87
lines changed

‎doc/src/sgml/backup.sgml

Lines changed: 4 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
<!-- $PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.136 2010/01/15 09:18:56 heikki Exp $ -->
1+
<!-- $PostgreSQL: pgsql/doc/src/sgml/backup.sgml,v 2.137 2010/01/23 16:37:12 sriggs Exp $ -->
22

33
<chapter id="backup">
44
<title>Backup and Restore</title>
@@ -2399,7 +2399,7 @@ primary_conninfo = 'host=192.168.1.50 port=5432 user=foo password=foopass'
23992399
</listitem>
24002400
<listitem>
24012401
<para>
2402-
Waiting to acquire buffer cleanup locks (for which there is no time out)
2402+
Waiting to acquire buffer cleanup locks
24032403
</para>
24042404
</listitem>
24052405
<listitem>
@@ -2536,11 +2536,7 @@ primary_conninfo = 'host=192.168.1.50 port=5432 user=foo password=foopass'
25362536
Three-way deadlocks are possible between AccessExclusiveLocks arriving from
25372537
the primary, cleanup WAL records that require buffer cleanup locks and
25382538
user requests that are waiting behind replayed AccessExclusiveLocks. Deadlocks
2539-
are currently resolved by the cancellation of user processes that would
2540-
need to wait on a lock. This is heavy-handed and generates more query
2541-
cancellations than we need to, though does remove the possibility of deadlock.
2542-
This behaviour is expected to improve substantially for the main release
2543-
version of 8.5.
2539+
are resolved by time-out when we exceed <varname>max_standby_delay</>.
25442540
</para>
25452541

25462542
<para>
@@ -2630,11 +2626,7 @@ LOG: database system is ready to accept read only connections
26302626
<varname>max_standby_delay</> or even set it to zero, though that is a
26312627
very aggressive setting. If the standby server is tasked as an additional
26322628
server for decision support queries then it may be acceptable to set this
2633-
to a value of many hours (in seconds). It is also possible to set
2634-
<varname>max_standby_delay</> to -1 which means wait forever for queries
2635-
to complete, if there are conflicts; this will be useful when performing
2636-
an archive recovery from a backup.
2637-
</para>
2629+
to a value of many hours (in seconds).
26382630

26392631
<para>
26402632
Transaction status "hint bits" written on primary are not WAL-logged,

‎doc/src/sgml/config.sgml

Lines changed: 8 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.244 2010/01/15 09:18:58 heikki Exp $ -->
1+
<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.245 2010/01/23 16:37:12 sriggs Exp $ -->
22

33
<chapter Id="runtime-config">
44
<title>Server Configuration</title>
@@ -1825,14 +1825,15 @@ archive_command = 'copy "%p" "C:\\server\\archivedir\\%f"' # Windows
18251825
<listitem>
18261826
<para>
18271827
When server acts as a standby, this parameter specifies a wait policy
1828-
for queries that conflict with incoming data changes. Valid settings
1829-
are -1, meaning wait forever, or a wait time of 0 or more seconds.
1830-
If a conflict should occur the server will delay up to this
1831-
amount before it begins trying to resolve things less amicably, as
1828+
for queries that conflict with data changes being replayed by recovery.
1829+
If a conflict should occur the server will delay up to this number
1830+
of seconds before it begins trying to resolve things less amicably, as
18321831
described in <xref linkend="hot-standby-conflict">. Typically,
18331832
this parameter makes sense only during replication, so when
1834-
performing an archive recovery to recover from data loss a
1835-
parameter setting of 0 is recommended. The default is 30 seconds.
1833+
performing an archive recovery to recover from data loss a very high
1834+
parameter setting is recommended. The default is 30 seconds.
1835+
There is no wait-forever setting because of the potential for deadlock
1836+
which that setting would introduce.
18361837
This parameter can only be set in the <filename>postgresql.conf</>
18371838
file or on the server command line.
18381839
</para>

‎src/backend/access/transam/xlog.c

Lines changed: 7 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.359 2010/01/20 19:43:40 heikki Exp $
10+
* $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.360 2010/01/23 16:37:12 sriggs Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -8803,9 +8803,12 @@ StartupProcessMain(void)
88038803
*/
88048804
pqsignal(SIGHUP,StartupProcSigHupHandler);/* reload config file */
88058805
pqsignal(SIGINT,SIG_IGN);/* ignore query cancel */
8806-
pqsignal(SIGTERM,StartupProcShutdownHandler);/* request shutdown */
8807-
pqsignal(SIGQUIT,startupproc_quickdie);/* hard crash time */
8808-
pqsignal(SIGALRM,SIG_IGN);
8806+
pqsignal(SIGTERM,StartupProcShutdownHandler);/* request shutdown */
8807+
pqsignal(SIGQUIT,startupproc_quickdie);/* hard crash time */
8808+
if (XLogRequestRecoveryConnections)
8809+
pqsignal(SIGALRM,handle_standby_sig_alarm);/* ignored unless InHotStandby */
8810+
else
8811+
pqsignal(SIGALRM,SIG_IGN);
88098812
pqsignal(SIGPIPE,SIG_IGN);
88108813
pqsignal(SIGUSR1,SIG_IGN);
88118814
pqsignal(SIGUSR2,SIG_IGN);

‎src/backend/storage/buffer/bufmgr.c

Lines changed: 38 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.254 2010/01/02 16:57:51 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.255 2010/01/23 16:37:12 sriggs Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -44,6 +44,7 @@
4444
#include"storage/ipc.h"
4545
#include"storage/proc.h"
4646
#include"storage/smgr.h"
47+
#include"storage/standby.h"
4748
#include"utils/rel.h"
4849
#include"utils/resowner.h"
4950

@@ -2417,13 +2418,48 @@ LockBufferForCleanup(Buffer buffer)
24172418
PinCountWaitBuf=bufHdr;
24182419
UnlockBufHdr(bufHdr);
24192420
LockBuffer(buffer,BUFFER_LOCK_UNLOCK);
2421+
24202422
/* Wait to be signaled by UnpinBuffer() */
2421-
ProcWaitForSignal();
2423+
if (InHotStandby)
2424+
{
2425+
/* Share the bufid that Startup process waits on */
2426+
SetStartupBufferPinWaitBufId(buffer-1);
2427+
/* Set alarm and then wait to be signaled by UnpinBuffer() */
2428+
ResolveRecoveryConflictWithBufferPin();
2429+
SetStartupBufferPinWaitBufId(-1);
2430+
}
2431+
else
2432+
ProcWaitForSignal();
2433+
24222434
PinCountWaitBuf=NULL;
24232435
/* Loop back and try again */
24242436
}
24252437
}
24262438

2439+
/*
2440+
* Check called from RecoveryConflictInterrupt handler when Startup
2441+
* process requests cancelation of all pin holders that are blocking it.
2442+
*/
2443+
bool
2444+
HoldingBufferPinThatDelaysRecovery(void)
2445+
{
2446+
intbufid=GetStartupBufferPinWaitBufId();
2447+
2448+
/*
2449+
* If we get woken slowly then it's possible that the Startup process
2450+
* was already woken by other backends before we got here. Also possible
2451+
* that we get here by multiple interrupts or interrupts at inappropriate
2452+
* times, so make sure we do nothing if the bufid is not set.
2453+
*/
2454+
if (bufid<0)
2455+
return false;
2456+
2457+
if (PrivateRefCount[bufid]>0)
2458+
return true;
2459+
2460+
return false;
2461+
}
2462+
24272463
/*
24282464
* ConditionalLockBufferForCleanup - as above, but don't wait to get the lock
24292465
*

‎src/backend/storage/ipc/procarray.c

Lines changed: 7 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -37,7 +37,7 @@
3737
*
3838
*
3939
* IDENTIFICATION
40-
* $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.58 2010/01/21 00:53:58 sriggs Exp $
40+
* $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.59 2010/01/23 16:37:12 sriggs Exp $
4141
*
4242
*-------------------------------------------------------------------------
4343
*/
@@ -1680,15 +1680,13 @@ GetCurrentVirtualXIDs(TransactionId limitXmin, bool excludeXmin0,
16801680
* latestCompletedXid since doing so would be a performance issue during
16811681
* normal running, so we check it essentially for free on the standby.
16821682
*
1683-
* If dbOid is valid we skip backends attached to other databases. Some
1684-
* callers choose to skipExistingConflicts.
1683+
* If dbOid is valid we skip backends attached to other databases.
16851684
*
16861685
* Be careful to *not* pfree the result from this function. We reuse
16871686
* this array sufficiently often that we use malloc for the result.
16881687
*/
16891688
VirtualTransactionId*
1690-
GetConflictingVirtualXIDs(TransactionIdlimitXmin,OiddbOid,
1691-
boolskipExistingConflicts)
1689+
GetConflictingVirtualXIDs(TransactionIdlimitXmin,OiddbOid)
16921690
{
16931691
staticVirtualTransactionId*vxids;
16941692
ProcArrayStruct*arrayP=procArray;
@@ -1727,9 +1725,6 @@ GetConflictingVirtualXIDs(TransactionId limitXmin, Oid dbOid,
17271725
if (proc->pid==0)
17281726
continue;
17291727

1730-
if (skipExistingConflicts&&proc->recoveryConflictPending)
1731-
continue;
1732-
17331728
if (!OidIsValid(dbOid)||
17341729
proc->databaseId==dbOid)
17351730
{
@@ -1886,7 +1881,7 @@ CountDBBackends(Oid databaseid)
18861881
* CancelDBBackends --- cancel backends that are using specified database
18871882
*/
18881883
void
1889-
CancelDBBackends(Oiddatabaseid)
1884+
CancelDBBackends(Oiddatabaseid,ProcSignalReasonsigmode,boolconflictPending)
18901885
{
18911886
ProcArrayStruct*arrayP=procArray;
18921887
intindex;
@@ -1899,22 +1894,21 @@ CancelDBBackends(Oid databaseid)
18991894
{
19001895
volatilePGPROC*proc=arrayP->procs[index];
19011896

1902-
if (proc->databaseId==databaseid)
1897+
if (databaseid==InvalidOid||proc->databaseId==databaseid)
19031898
{
19041899
VirtualTransactionIdprocvxid;
19051900

19061901
GET_VXID_FROM_PGPROC(procvxid,*proc);
19071902

1908-
proc->recoveryConflictPending=true;
1903+
proc->recoveryConflictPending=conflictPending;
19091904
pid=proc->pid;
19101905
if (pid!=0)
19111906
{
19121907
/*
19131908
* Kill the pid if it's still here. If not, that's what we wanted
19141909
* so ignore any errors.
19151910
*/
1916-
(void)SendProcSignal(pid,PROCSIG_RECOVERY_CONFLICT_DATABASE,
1917-
procvxid.backendId);
1911+
(void)SendProcSignal(pid,sigmode,procvxid.backendId);
19181912
}
19191913
}
19201914
}

‎src/backend/storage/ipc/procsignal.c

Lines changed: 4 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/storage/ipc/procsignal.c,v 1.3 2010/01/16 10:05:50 sriggs Exp $
11+
* $PostgreSQL: pgsql/src/backend/storage/ipc/procsignal.c,v 1.4 2010/01/23 16:37:12 sriggs Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -272,5 +272,8 @@ procsignal_sigusr1_handler(SIGNAL_ARGS)
272272
if (CheckProcSignal(PROCSIG_RECOVERY_CONFLICT_SNAPSHOT))
273273
RecoveryConflictInterrupt(PROCSIG_RECOVERY_CONFLICT_SNAPSHOT);
274274

275+
if (CheckProcSignal(PROCSIG_RECOVERY_CONFLICT_BUFFERPIN))
276+
RecoveryConflictInterrupt(PROCSIG_RECOVERY_CONFLICT_BUFFERPIN);
277+
275278
errno=save_errno;
276279
}

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