/*
* Backend-shutdown callback. Do cleanup that we want to be sure happens
* before all the supporting modules begin to nail their doors shut via
* their own callbacks.
*
* User-level cleanup, such as temp-relation removal and UNLISTEN, happens
* via separate callbacks that execute before this one. We don't combine the
* callbacks because we still want this one to happen if the user-level
* cleanup fails.
*/
static void
ShutdownPostgres(int code, Datum arg)
{
/* Make sure we've killed any active transaction */
AbortOutOfAnyTransaction();
/*
* User locks are not released by transaction end, so be sure to release
* them explicitly.
*/
LockReleaseAll(USER_LOCKMETHOD, true);
}
static void
DiscardAll(bool isTopLevel)
{
/*
* Disallow DISCARD ALL in a transaction block. This is arguably
* inconsistent (we don't make a similar check in the command sequence
* that DISCARD ALL is equivalent to), but the idea is to catch mistakes:
* DISCARD ALL inside a transaction block would leave the transaction
* still uncommitted.
*/
PreventTransactionChain(isTopLevel, "DISCARD ALL");
SetPGVariable("session_authorization", NIL, false);
ResetAllOptions();
DropAllPreparedStatements();
PortalHashTableDeleteAll();
Async_UnlistenAll();
LockReleaseAll(USER_LOCKMETHOD, true);
ResetPlanCache();
ResetTempTableNamespace();
}
/*
* Backend-shutdown callback. Do cleanup that we want to be sure happens
* before all the supporting modules begin to nail their doors shut via
* their own callbacks.
*
* User-level cleanup, such as temp-relation removal and UNLISTEN, happens
* via separate callbacks that execute before this one. We don't combine the
* callbacks because we still want this one to happen if the user-level
* cleanup fails.
*/
static void
ShutdownPostgres(int code, Datum arg)
{
/* Make sure we've killed any active transaction */
AbortOutOfAnyTransaction();
/*
* If there was a segment OOM for which we haven't already reported
* our usage, report now.
*/
ReportOOMConsumption();
/* Disable memory protection */
GPMemoryProtect_Shutdown();
/* Release SessionState entry */
SessionState_Shutdown();
/*
* User locks are not released by transaction end, so be sure to release
* them explicitly.
*/
LockReleaseAll(USER_LOCKMETHOD, true);
}
void
FileRepSubProcess_Main()
{
const char *statmsg;
MemoryContext fileRepSubProcessMemoryContext;
sigjmp_buf local_sigjmp_buf;
MyProcPid = getpid();
MyStartTime = time(NULL);
/*
* Create a PGPROC so we can use LWLocks in FileRep sub-processes. The
* routine also register clean up at process exit
*/
InitAuxiliaryProcess();
InitBufferPoolBackend();
FileRepSubProcess_ConfigureSignals();
/*
* If an exception is encountered, processing resumes here.
*
* See notes in postgres.c about the design of this coding.
*/
if (sigsetjmp(local_sigjmp_buf, 1) != 0)
{
/* Prevents interrupts while cleaning up */
HOLD_INTERRUPTS();
/* Report the error to the server log */
EmitErrorReport();
LWLockReleaseAll();
if (FileRepPrimary_IsResyncManagerOrWorker())
{
LockReleaseAll(DEFAULT_LOCKMETHOD, false);
}
if (FileRepIsBackendSubProcess(fileRepProcessType))
{
AbortBufferIO();
UnlockBuffers();
/* buffer pins are released here: */
ResourceOwnerRelease(CurrentResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
}
/*
* We can now go away. Note that because we'll call InitProcess, a
* callback will be registered to do ProcKill, which will clean up
* necessary state.
*/
proc_exit(0);
}
/* We can now handle ereport(ERROR) */
PG_exception_stack = &local_sigjmp_buf;
PG_SETMASK(&UnBlockSig);
/*
* Identify myself via ps
*/
statmsg = FileRepProcessTypeToString[fileRepProcessType];
init_ps_display(statmsg, "", "", "");
/* Create the memory context where cross-transaction state is stored */
fileRepSubProcessMemoryContext = AllocSetContextCreate(TopMemoryContext,
"filerep subprocess memory context",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
MemoryContextSwitchTo(fileRepSubProcessMemoryContext);
stateChangeRequestCounter++;
FileRepSubProcess_ProcessSignals();
switch (fileRepProcessType)
{
case FileRepProcessTypePrimarySender:
FileRepPrimary_StartSender();
break;
case FileRepProcessTypeMirrorReceiver:
FileRepMirror_StartReceiver();
break;
case FileRepProcessTypeMirrorConsumer:
case FileRepProcessTypeMirrorConsumerWriter:
case FileRepProcessTypeMirrorConsumerAppendOnly1:
FileRepMirror_StartConsumer();
break;
case FileRepProcessTypeMirrorSenderAck:
FileRepAckMirror_StartSender();
break;
case FileRepProcessTypePrimaryReceiverAck:
FileRepAckPrimary_StartReceiver();
break;
case FileRepProcessTypePrimaryConsumerAck:
FileRepAckPrimary_StartConsumer();
break;
case FileRepProcessTypePrimaryRecovery:
FileRepSubProcess_InitProcess();
/*
* At this point, database is starting up and xlog is not yet
* replayed. Initializing relcache now is dangerous, a sequential
* scan of catalog tables may end up with incorrect hint bits.
* E.g. a committed transaction's dirty heap pages made it to disk
* but pg_clog update was still in memory and we crashed. If a
* tuple inserted by this transaction is read during relcache
* initialization, status of the tuple's xmin will be incorrectly
* determined as "not commited" from pg_clog. And
* HEAP_XMIN_INVALID hint bit will be set, rendering the tuple
* perpetually invisible. Relcache initialization must be
* deferred to only after all of xlog has been replayed.
*/
FileRepPrimary_StartRecovery();
ResourceOwnerRelease(CurrentResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
break;
case FileRepProcessTypeResyncManager:
FileRepSubProcess_InitProcess();
FileRepPrimary_StartResyncManager();
ResourceOwnerRelease(CurrentResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
break;
case FileRepProcessTypeResyncWorker1:
case FileRepProcessTypeResyncWorker2:
case FileRepProcessTypeResyncWorker3:
case FileRepProcessTypeResyncWorker4:
FileRepSubProcess_InitProcess();
FileRepPrimary_StartResyncWorker();
ResourceOwnerRelease(CurrentResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
break;
default:
elog(PANIC, "unrecognized process type: %s(%d)",
statmsg, fileRepProcessType);
break;
}
switch (FileRepSubProcess_GetState())
{
case FileRepStateShutdown:
case FileRepStateReady:
proc_exit(0);
break;
default:
proc_exit(2);
break;
}
}
/*
* SIGUSR2 signal from main file rep process
*/
static void
FileRepSubProcess_ShutdownHandler(SIGNAL_ARGS)
{
bool isInTransition = FALSE;
DataState_e dataStateTransition;
shutdownRequested = true;
/*
* Exit the process if recv() call is hanging or compacting is running.
* Compacting can take many minutes.
*/
if (fileRepProcessType == FileRepProcessTypePrimaryReceiverAck ||
fileRepProcessType == FileRepProcessTypeMirrorReceiver ||
fileRepProcessType == FileRepProcessTypePrimaryRecovery)
{
/* workaround for gcov testing */
if (Debug_filerep_gcov)
{
getFileRepRoleAndState(&fileRepRole, &segmentState, &dataState, &isInTransition, &dataStateTransition);
if (isInTransition == TRUE &&
dataStateTransition == DataStateInChangeTracking)
{
proc_exit(0);
return;
}
}
die(PASS_SIGNAL_ARGS);
}
if (FileRepIsBackendSubProcess(fileRepProcessType))
{
if (FileRepPrimary_IsResyncManagerOrWorker())
{
getFileRepRoleAndState(&fileRepRole, &segmentState, &dataState, &isInTransition, &dataStateTransition);
if (isInTransition == TRUE &&
dataStateTransition == DataStateInChangeTracking)
{
/*
* Resync workers and manager may be waiting on lock that is
* acquired by backend process that is suspended during
* transition to Change Tracking and so FileRep backend
* shutdown may never be completed.
*/
if (fileRepProcessType == FileRepProcessTypeResyncManager)
{
FileRepResync_Cleanup();
}
else
{
LockReleaseAll(DEFAULT_LOCKMETHOD, false);
}
/*
* We remove ourself from LW waiter list (if applicable).
*
* If the current backend is waiting on a LWLock and exits w/o
* any cleanup (remove from waiters list) it can cause a
* breakage in the LWlock's waiters linked list after it dies.
* This can lead to unpleasant issues causing starvation for
* subsequent waiters because the current backend is already
* dead without assigning the LWLock to the next waiter.
*
* XXX Side note - Although implemented here, avoid exiting
* inside an signal handler.
*/
LWLockWaitCancel();
LWLockReleaseAll();
proc_exit(0);
return;
}
}
/*
* call the normal postgres die so that it requests query
* cancel/procdie
*/
die(PASS_SIGNAL_ARGS);
}
}
