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In HS, Startup process sets SIGALRM when waiting for buffer pin. If

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woken by alarm we send SIGUSR1 to all backends requesting that they
check to see if they are blocking Startup process. If so, they throw
ERROR/FATAL as for other conflict resolutions. Deadlock stop gap
removed. max_standby_delay = -1 option removed to prevent deadlock.
This commit is contained in:
Simon Riggs
2010-01-23 16:37:12 +00:00
parent 4fa69e566c
commit 959ac58c04
16 changed files with 367 additions and 87 deletions
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40
src/backend/storage/buffer/bufmgr.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.254 2010/01/02 16:57:51 momjian Exp $
* $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.255 2010/01/23 16:37:12 sriggs Exp $
*
*-------------------------------------------------------------------------
*/
@ -44,6 +44,7 @@
#include "storage/ipc.h"
#include "storage/proc.h"
#include "storage/smgr.h"
#include "storage/standby.h"
#include "utils/rel.h"
#include "utils/resowner.h"
@ -2417,13 +2418,48 @@ LockBufferForCleanup(Buffer buffer)
PinCountWaitBuf = bufHdr;
UnlockBufHdr(bufHdr);
LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
/* Wait to be signaled by UnpinBuffer() */
ProcWaitForSignal();
if (InHotStandby)
{
/* Share the bufid that Startup process waits on */
SetStartupBufferPinWaitBufId(buffer - 1);
/* Set alarm and then wait to be signaled by UnpinBuffer() */
ResolveRecoveryConflictWithBufferPin();
SetStartupBufferPinWaitBufId(-1);
}
else
ProcWaitForSignal();
PinCountWaitBuf = NULL;
/* Loop back and try again */
}
}
/*
* Check called from RecoveryConflictInterrupt handler when Startup
* process requests cancelation of all pin holders that are blocking it.
*/
bool
HoldingBufferPinThatDelaysRecovery(void)
{
int bufid = GetStartupBufferPinWaitBufId();
/*
* If we get woken slowly then it's possible that the Startup process
* was already woken by other backends before we got here. Also possible
* that we get here by multiple interrupts or interrupts at inappropriate
* times, so make sure we do nothing if the bufid is not set.
*/
if (bufid < 0)
return false;
if (PrivateRefCount[bufid] > 0)
return true;
return false;
}
/*
* ConditionalLockBufferForCleanup - as above, but don't wait to get the lock
*