Beispiel #1
0
int main(int argc, char* argv[])
{
	cmockery_parse_arguments(argc, argv);

	const UnitTest tests[] =
	{
	unit_test(test__resetSessionForPrimaryGangLoss),
	unit_test(test__createWriterGang),
	unit_test(test__createReaderGang), };

	MemoryContextInit();
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "gang test");
	Gp_role = GP_ROLE_DISPATCH;
	GpIdentity.numsegments = TOTOAL_SEGMENTS;
	GpIdentity.dbid = 1;
	GpIdentity.segindex = -1;
	gp_connections_per_thread = 64;

	Port procport;
	MyProcPort = &procport;
	MyProcPort->database_name = "test";
	MyProcPort->user_name = "gpadmin";

	s_cdb = makeTestCdb(1, TOTOAL_SEGMENTS);

	return run_tests(tests);
}
Beispiel #2
0
/*
 * Main worker routine. Accepts dsm_handle as an argument
 */
static void
bg_worker_main(Datum main_arg)
{
	PartitionArgs  *args;
	dsm_handle		handle = DatumGetInt32(main_arg);

	/* Create resource owner */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "CreatePartitionsWorker");

	/* Attach to dynamic shared memory */
	if (!handle)
	{
		ereport(WARNING,
                (errmsg("pg_pathman worker: invalid dsm_handle")));
	}
	segment = dsm_attach(handle);
	args = dsm_segment_address(segment);

	/* Establish connection and start transaction */
	BackgroundWorkerInitializeConnectionByOid(args->dbid, InvalidOid);
	StartTransactionCommand();
	SPI_connect();
	PushActiveSnapshot(GetTransactionSnapshot());

	/* Create partitions */
	args->result = create_partitions(args->relid, PATHMAN_GET_DATUM(args->value, args->by_val), args->value_type, &args->crashed);

	/* Cleanup */
	SPI_finish();
	PopActiveSnapshot();
	CommitTransactionCommand();

	dsm_detach(segment);
}
Beispiel #3
0
/* Main entry point for walsender process */
int
WalSenderMain(void)
{
	MemoryContext walsnd_context;

	am_cascading_walsender = RecoveryInProgress();

	/* Create a per-walsender data structure in shared memory */
	InitWalSnd();

	/*
	 * Create a memory context that we will do all our work in.  We do this so
	 * that we can reset the context during error recovery and thereby avoid
	 * possible memory leaks.  Formerly this code just ran in
	 * TopMemoryContext, but resetting that would be a really bad idea.
	 *
	 * XXX: we don't actually attempt error recovery in walsender, we just
	 * close the connection and exit.
	 */
	walsnd_context = AllocSetContextCreate(TopMemoryContext,
										   "Wal Sender",
										   ALLOCSET_DEFAULT_MINSIZE,
										   ALLOCSET_DEFAULT_INITSIZE,
										   ALLOCSET_DEFAULT_MAXSIZE);
	MemoryContextSwitchTo(walsnd_context);

	/* Set up resource owner */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "walsender top-level resource owner");

	/* Unblock signals (they were blocked when the postmaster forked us) */
	PG_SETMASK(&UnBlockSig);

	/*
	 * Use the recovery target timeline ID during recovery
	 */
	if (am_cascading_walsender)
		ThisTimeLineID = GetRecoveryTargetTLI();

	/* Tell the standby that walsender is ready for receiving commands */
	ReadyForQuery(DestRemote);

	/* Handle handshake messages before streaming */
	WalSndHandshake();

	/* Initialize shared memory status */
	{
		/* use volatile pointer to prevent code rearrangement */
		volatile WalSnd *walsnd = MyWalSnd;

		SpinLockAcquire(&walsnd->mutex);
		walsnd->sentPtr = sentPtr;
		SpinLockRelease(&walsnd->mutex);
	}

	SyncRepInitConfig();

	/* Main loop of walsender */
	return WalSndLoop();
}
Beispiel #4
0
/*
 * CreatePortal
 *		Returns a new portal given a name.
 *
 * allowDup: if true, automatically drop any pre-existing portal of the
 * same name (if false, an error is raised).
 *
 * dupSilent: if true, don't even emit a WARNING.
 */
Portal
CreatePortal(const char *name, bool allowDup, bool dupSilent)
{
	Portal		portal;

	AssertArg(PointerIsValid(name));

	portal = GetPortalByName(name);
	if (PortalIsValid(portal))
	{
		if (!allowDup)
			ereport(ERROR,
					(errcode(ERRCODE_DUPLICATE_CURSOR),
					 errmsg("cursor \"%s\" already exists", name)));
		if (!dupSilent)
			ereport(WARNING,
					(errcode(ERRCODE_DUPLICATE_CURSOR),
					 errmsg("closing existing cursor \"%s\"",
							name)));
		PortalDrop(portal, false);
	}

	/* make new portal structure */
	portal = (Portal) MemoryContextAllocZero(PortalMemory, sizeof *portal);

	/* initialize portal heap context; typically it won't store much */
	portal->heap = AllocSetContextCreate(PortalMemory,
										 "PortalHeapMemory",
										 ALLOCSET_SMALL_MINSIZE,
										 ALLOCSET_SMALL_INITSIZE,
										 ALLOCSET_SMALL_MAXSIZE);

	/* create a resource owner for the portal */
	portal->resowner = ResourceOwnerCreate(CurTransactionResourceOwner,
										   "Portal");

	/* initialize portal fields that don't start off zero */
	portal->cleanup = PortalCleanup;
	portal->createSubid = GetCurrentSubTransactionId();
	portal->strategy = PORTAL_MULTI_QUERY;
	portal->cursorOptions = CURSOR_OPT_NO_SCROLL;
	portal->atStart = true;
	portal->atEnd = true;		/* disallow fetches until query is set */

	/* put portal in table (sets portal->name) */
	PortalHashTableInsert(portal, name);

	return portal;
}
Beispiel #5
0
/*
 * Establish an AuxProcessResourceOwner for the current process.
 */
void
CreateAuxProcessResourceOwner(void)
{
	Assert(AuxProcessResourceOwner == NULL);
	Assert(CurrentResourceOwner == NULL);
	AuxProcessResourceOwner = ResourceOwnerCreate(NULL, "AuxiliaryProcess");
	CurrentResourceOwner = AuxProcessResourceOwner;

	/*
	 * Register a shmem-exit callback for cleanup of aux-process resource
	 * owner.  (This needs to run after, e.g., ShutdownXLOG.)
	 */
	on_shmem_exit(ReleaseAuxProcessResourcesCallback, 0);

}
static void
FileRepSubProcess_InitProcess(void)
{
	SetProcessingMode(InitProcessing);

	/*
	 * Create a resource owner to keep track of our resources
	 */
	CurrentResourceOwner = ResourceOwnerCreate(NULL,
											   FileRepProcessTypeToString[fileRepProcessType]);


	InitXLOGAccess();

	SetProcessingMode(NormalProcessing);

	InitBufferPoolAccess();

	/*
	 * Don't add Filerep backend subprocesses to the proc array.
	 *
	 * This avoids any deadlock situations during Filerep transition. E.g. If
	 * a normal backend has acquired ProcArrayLock and is waiting for Filerep
	 * transition to finish, the Filerep backend subprocesses will deadlock
	 * forever as they can't acquire the ProcArray lock to remove themselves
	 * from the ProcArray. This directly causes the transition to stall and
	 * thus the whole system.
	 */

	/*
	 * Initialize my entry in the shared-invalidation manager's array of
	 * per-backend data.
	 *
	 * Sets up MyBackendId, a unique backend identifier.
	 */
	MyBackendId = InvalidBackendId;

	SharedInvalBackendInit(false);

	if (MyBackendId > MaxBackends || MyBackendId <= 0)
		elog(FATAL, "bad backend id: %d", MyBackendId);

	/*
	 * bufmgr needs another initialization call too
	 */
	InitBufferPoolBackend();
}
Beispiel #7
0
/*
 * SetResQueueId -- set the cached value for the current resource queue.
 *
 * Notes
 *	Needs to be called at session initialization and after (or in) SET ROLE.
 */
void
SetResQueueId(void)
{
	/* to cave the code of cache part, we provide a resource owner here if no
	 * existing */
	ResourceOwner owner = NULL;

	if (CurrentResourceOwner == NULL)
	{
		owner = ResourceOwnerCreate(NULL, "SetResQueueId");
		CurrentResourceOwner = owner;
	}

	MyQueueId = GetResQueueForRole(GetUserId());

	if (owner)
	{
		CurrentResourceOwner = NULL;
		ResourceOwnerDelete(owner);
	}

	return;
}
Beispiel #8
0
/* attach worker to the shared memory segment, read the job structure */
static void
initialize_worker(uint32 segment)
{
	dsm_segment   *seg;
	ResourceOwner old,
				  tmp;
	/* Connect to dynamic shared memory segment.
	 *
	 * In order to attach a dynamic shared memory segment, we need a
	 * resource owner. We cannot to StartTransactionCommand here, since
	 * we haven't yet attached to the database: to do this, we need to
	 * fetch information about connection properties from the shared
	 * memory segment.
	 */
	 old = CurrentResourceOwner;
	 CurrentResourceOwner = ResourceOwnerCreate(NULL, "Background Worker");
	 seg = dsm_attach(segment);
	 if (seg == NULL)
	 	ereport(ERROR,
	 			(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
	 			 errmsg("unable to map dynamic shared memory segment")));
	 dsm_pin_mapping(seg);
	 tmp = CurrentResourceOwner;
	 CurrentResourceOwner = old;
	 ResourceOwnerDelete(tmp);

	 job = palloc(sizeof(JobDesc));
	 /* copy the arguments from shared memory segment */
	 memcpy(job, dsm_segment_address(seg), sizeof(JobDesc));

	 /* and detach it right away */
	 dsm_detach(seg);
	 Assert(job->magic == JOB_MAGIC);

	 job_run_function.schema = quote_identifier(job->schemaname);
	 job_run_function.name = quote_identifier("run_job");
}
Beispiel #9
0
/*
 * Main entry point for checkpointer process
 *
 * This is invoked from AuxiliaryProcessMain, which has already created the
 * basic execution environment, but not enabled signals yet.
 */
void
CheckpointerMain(void)
{
	sigjmp_buf	local_sigjmp_buf;
	MemoryContext checkpointer_context;

	CheckpointerShmem->checkpointer_pid = MyProcPid;

	/*
	 * Properly accept or ignore signals the postmaster might send us
	 *
	 * Note: we deliberately ignore SIGTERM, because during a standard Unix
	 * system shutdown cycle, init will SIGTERM all processes at once.  We
	 * want to wait for the backends to exit, whereupon the postmaster will
	 * tell us it's okay to shut down (via SIGUSR2).
	 */
	pqsignal(SIGHUP, ChkptSigHupHandler);		/* set flag to read config
												 * file */
	pqsignal(SIGINT, ReqCheckpointHandler);		/* request checkpoint */
	pqsignal(SIGTERM, SIG_IGN); /* ignore SIGTERM */
	pqsignal(SIGQUIT, chkpt_quickdie);	/* hard crash time */
	pqsignal(SIGALRM, SIG_IGN);
	pqsignal(SIGPIPE, SIG_IGN);
	pqsignal(SIGUSR1, chkpt_sigusr1_handler);
	pqsignal(SIGUSR2, ReqShutdownHandler);		/* request shutdown */

	/*
	 * Reset some signals that are accepted by postmaster but not here
	 */
	pqsignal(SIGCHLD, SIG_DFL);
	pqsignal(SIGTTIN, SIG_DFL);
	pqsignal(SIGTTOU, SIG_DFL);
	pqsignal(SIGCONT, SIG_DFL);
	pqsignal(SIGWINCH, SIG_DFL);

	/* We allow SIGQUIT (quickdie) at all times */
	sigdelset(&BlockSig, SIGQUIT);

	/*
	 * Initialize so that first time-driven event happens at the correct time.
	 */
	last_checkpoint_time = last_xlog_switch_time = (pg_time_t) time(NULL);

	/*
	 * Create a resource owner to keep track of our resources (currently only
	 * buffer pins).
	 */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "Checkpointer");

	/*
	 * Create a memory context that we will do all our work in.  We do this so
	 * that we can reset the context during error recovery and thereby avoid
	 * possible memory leaks.  Formerly this code just ran in
	 * TopMemoryContext, but resetting that would be a really bad idea.
	 */
	checkpointer_context = AllocSetContextCreate(TopMemoryContext,
												 "Checkpointer",
												 ALLOCSET_DEFAULT_SIZES);
	MemoryContextSwitchTo(checkpointer_context);

	/*
	 * 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)
	{
		/* Since not using PG_TRY, must reset error stack by hand */
		error_context_stack = NULL;

		/* Prevent interrupts while cleaning up */
		HOLD_INTERRUPTS();

		/* Report the error to the server log */
		EmitErrorReport();

		/*
		 * These operations are really just a minimal subset of
		 * AbortTransaction().  We don't have very many resources to worry
		 * about in checkpointer, but we do have LWLocks, buffers, and temp
		 * files.
		 */
		LWLockReleaseAll();
		ConditionVariableCancelSleep();
		pgstat_report_wait_end();
		AbortBufferIO();
		UnlockBuffers();
		/* buffer pins are released here: */
		ResourceOwnerRelease(CurrentResourceOwner,
							 RESOURCE_RELEASE_BEFORE_LOCKS,
							 false, true);
		/* we needn't bother with the other ResourceOwnerRelease phases */
		AtEOXact_Buffers(false);
		AtEOXact_SMgr();
		AtEOXact_Files();
		AtEOXact_HashTables(false);

		/* Warn any waiting backends that the checkpoint failed. */
		if (ckpt_active)
		{
			SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
			CheckpointerShmem->ckpt_failed++;
			CheckpointerShmem->ckpt_done = CheckpointerShmem->ckpt_started;
			SpinLockRelease(&CheckpointerShmem->ckpt_lck);

			ckpt_active = false;
		}

		/*
		 * Now return to normal top-level context and clear ErrorContext for
		 * next time.
		 */
		MemoryContextSwitchTo(checkpointer_context);
		FlushErrorState();

		/* Flush any leaked data in the top-level context */
		MemoryContextResetAndDeleteChildren(checkpointer_context);

		/* Now we can allow interrupts again */
		RESUME_INTERRUPTS();

		/*
		 * Sleep at least 1 second after any error.  A write error is likely
		 * to be repeated, and we don't want to be filling the error logs as
		 * fast as we can.
		 */
		pg_usleep(1000000L);

		/*
		 * Close all open files after any error.  This is helpful on Windows,
		 * where holding deleted files open causes various strange errors.
		 * It's not clear we need it elsewhere, but shouldn't hurt.
		 */
		smgrcloseall();
	}

	/* We can now handle ereport(ERROR) */
	PG_exception_stack = &local_sigjmp_buf;

	/*
	 * Unblock signals (they were blocked when the postmaster forked us)
	 */
	PG_SETMASK(&UnBlockSig);

	/*
	 * Ensure all shared memory values are set correctly for the config. Doing
	 * this here ensures no race conditions from other concurrent updaters.
	 */
	UpdateSharedMemoryConfig();

	/*
	 * Advertise our latch that backends can use to wake us up while we're
	 * sleeping.
	 */
	ProcGlobal->checkpointerLatch = &MyProc->procLatch;

	/*
	 * Loop forever
	 */
	for (;;)
	{
		bool		do_checkpoint = false;
		int			flags = 0;
		pg_time_t	now;
		int			elapsed_secs;
		int			cur_timeout;
		int			rc;

		/* Clear any already-pending wakeups */
		ResetLatch(MyLatch);

		/*
		 * Process any requests or signals received recently.
		 */
		AbsorbFsyncRequests();

		if (got_SIGHUP)
		{
			got_SIGHUP = false;
			ProcessConfigFile(PGC_SIGHUP);

			/*
			 * Checkpointer is the last process to shut down, so we ask it to
			 * hold the keys for a range of other tasks required most of which
			 * have nothing to do with checkpointing at all.
			 *
			 * For various reasons, some config values can change dynamically
			 * so the primary copy of them is held in shared memory to make
			 * sure all backends see the same value.  We make Checkpointer
			 * responsible for updating the shared memory copy if the
			 * parameter setting changes because of SIGHUP.
			 */
			UpdateSharedMemoryConfig();
		}
		if (checkpoint_requested)
		{
			checkpoint_requested = false;
			do_checkpoint = true;
			BgWriterStats.m_requested_checkpoints++;
		}
		if (shutdown_requested)
		{
			/*
			 * From here on, elog(ERROR) should end with exit(1), not send
			 * control back to the sigsetjmp block above
			 */
			ExitOnAnyError = true;
			/* Close down the database */
			ShutdownXLOG(0, 0);
			/* Normal exit from the checkpointer is here */
			proc_exit(0);		/* done */
		}

		/*
		 * Force a checkpoint if too much time has elapsed since the last one.
		 * Note that we count a timed checkpoint in stats only when this
		 * occurs without an external request, but we set the CAUSE_TIME flag
		 * bit even if there is also an external request.
		 */
		now = (pg_time_t) time(NULL);
		elapsed_secs = now - last_checkpoint_time;
		if (elapsed_secs >= CheckPointTimeout)
		{
			if (!do_checkpoint)
				BgWriterStats.m_timed_checkpoints++;
			do_checkpoint = true;
			flags |= CHECKPOINT_CAUSE_TIME;
		}

		/*
		 * Do a checkpoint if requested.
		 */
		if (do_checkpoint)
		{
			bool		ckpt_performed = false;
			bool		do_restartpoint;

			/*
			 * Check if we should perform a checkpoint or a restartpoint. As a
			 * side-effect, RecoveryInProgress() initializes TimeLineID if
			 * it's not set yet.
			 */
			do_restartpoint = RecoveryInProgress();

			/*
			 * Atomically fetch the request flags to figure out what kind of a
			 * checkpoint we should perform, and increase the started-counter
			 * to acknowledge that we've started a new checkpoint.
			 */
			SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
			flags |= CheckpointerShmem->ckpt_flags;
			CheckpointerShmem->ckpt_flags = 0;
			CheckpointerShmem->ckpt_started++;
			SpinLockRelease(&CheckpointerShmem->ckpt_lck);

			/*
			 * The end-of-recovery checkpoint is a real checkpoint that's
			 * performed while we're still in recovery.
			 */
			if (flags & CHECKPOINT_END_OF_RECOVERY)
				do_restartpoint = false;

			/*
			 * We will warn if (a) too soon since last checkpoint (whatever
			 * caused it) and (b) somebody set the CHECKPOINT_CAUSE_XLOG flag
			 * since the last checkpoint start.  Note in particular that this
			 * implementation will not generate warnings caused by
			 * CheckPointTimeout < CheckPointWarning.
			 */
			if (!do_restartpoint &&
				(flags & CHECKPOINT_CAUSE_XLOG) &&
				elapsed_secs < CheckPointWarning)
				ereport(LOG,
						(errmsg_plural("checkpoints are occurring too frequently (%d second apart)",
				"checkpoints are occurring too frequently (%d seconds apart)",
									   elapsed_secs,
									   elapsed_secs),
						 errhint("Consider increasing the configuration parameter \"max_wal_size\".")));

			/*
			 * Initialize checkpointer-private variables used during
			 * checkpoint.
			 */
			ckpt_active = true;
			if (do_restartpoint)
				ckpt_start_recptr = GetXLogReplayRecPtr(NULL);
			else
				ckpt_start_recptr = GetInsertRecPtr();
			ckpt_start_time = now;
			ckpt_cached_elapsed = 0;

			/*
			 * Do the checkpoint.
			 */
			if (!do_restartpoint)
			{
				CreateCheckPoint(flags);
				ckpt_performed = true;
			}
			else
				ckpt_performed = CreateRestartPoint(flags);

			/*
			 * After any checkpoint, close all smgr files.  This is so we
			 * won't hang onto smgr references to deleted files indefinitely.
			 */
			smgrcloseall();

			/*
			 * Indicate checkpoint completion to any waiting backends.
			 */
			SpinLockAcquire(&CheckpointerShmem->ckpt_lck);
			CheckpointerShmem->ckpt_done = CheckpointerShmem->ckpt_started;
			SpinLockRelease(&CheckpointerShmem->ckpt_lck);

			if (ckpt_performed)
			{
				/*
				 * Note we record the checkpoint start time not end time as
				 * last_checkpoint_time.  This is so that time-driven
				 * checkpoints happen at a predictable spacing.
				 */
				last_checkpoint_time = now;
			}
			else
			{
				/*
				 * We were not able to perform the restartpoint (checkpoints
				 * throw an ERROR in case of error).  Most likely because we
				 * have not received any new checkpoint WAL records since the
				 * last restartpoint. Try again in 15 s.
				 */
				last_checkpoint_time = now - CheckPointTimeout + 15;
			}

			ckpt_active = false;
		}

		/* Check for archive_timeout and switch xlog files if necessary. */
		CheckArchiveTimeout();

		/*
		 * Send off activity statistics to the stats collector.  (The reason
		 * why we re-use bgwriter-related code for this is that the bgwriter
		 * and checkpointer used to be just one process.  It's probably not
		 * worth the trouble to split the stats support into two independent
		 * stats message types.)
		 */
		pgstat_send_bgwriter();

		/*
		 * Sleep until we are signaled or it's time for another checkpoint or
		 * xlog file switch.
		 */
		now = (pg_time_t) time(NULL);
		elapsed_secs = now - last_checkpoint_time;
		if (elapsed_secs >= CheckPointTimeout)
			continue;			/* no sleep for us ... */
		cur_timeout = CheckPointTimeout - elapsed_secs;
		if (XLogArchiveTimeout > 0 && !RecoveryInProgress())
		{
			elapsed_secs = now - last_xlog_switch_time;
			if (elapsed_secs >= XLogArchiveTimeout)
				continue;		/* no sleep for us ... */
			cur_timeout = Min(cur_timeout, XLogArchiveTimeout - elapsed_secs);
		}

		rc = WaitLatch(MyLatch,
					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
					   cur_timeout * 1000L /* convert to ms */,
					   WAIT_EVENT_CHECKPOINTER_MAIN);

		/*
		 * Emergency bailout if postmaster has died.  This is to avoid the
		 * necessity for manual cleanup of all postmaster children.
		 */
		if (rc & WL_POSTMASTER_DEATH)
			exit(1);
	}
}
Beispiel #10
0
/*
 * Main entry point for walwriter process
 *
 * This is invoked from AuxiliaryProcessMain, which has already created the
 * basic execution environment, but not enabled signals yet.
 */
void
WalWriterMain(void)
{
	sigjmp_buf	local_sigjmp_buf;
	MemoryContext walwriter_context;
	int			left_till_hibernate;
	bool		hibernating;

	/*
	 * Properly accept or ignore signals the postmaster might send us
	 *
	 * We have no particular use for SIGINT at the moment, but seems
	 * reasonable to treat like SIGTERM.
	 */
	pqsignal(SIGHUP, WalSigHupHandler); /* set flag to read config file */
	pqsignal(SIGINT, WalShutdownHandler);		/* request shutdown */
	pqsignal(SIGTERM, WalShutdownHandler);		/* request shutdown */
	pqsignal(SIGQUIT, wal_quickdie);	/* hard crash time */
	pqsignal(SIGALRM, SIG_IGN);
	pqsignal(SIGPIPE, SIG_IGN);
	pqsignal(SIGUSR1, walwriter_sigusr1_handler);
	pqsignal(SIGUSR2, SIG_IGN); /* not used */

	/*
	 * Reset some signals that are accepted by postmaster but not here
	 */
	pqsignal(SIGCHLD, SIG_DFL);
	pqsignal(SIGTTIN, SIG_DFL);
	pqsignal(SIGTTOU, SIG_DFL);
	pqsignal(SIGCONT, SIG_DFL);
	pqsignal(SIGWINCH, SIG_DFL);

	/* We allow SIGQUIT (quickdie) at all times */
	sigdelset(&BlockSig, SIGQUIT);

	/*
	 * Create a resource owner to keep track of our resources (not clear that
	 * we need this, but may as well have one).
	 */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "Wal Writer");

	/*
	 * Create a memory context that we will do all our work in.  We do this so
	 * that we can reset the context during error recovery and thereby avoid
	 * possible memory leaks.  Formerly this code just ran in
	 * TopMemoryContext, but resetting that would be a really bad idea.
	 */
	walwriter_context = AllocSetContextCreate(TopMemoryContext,
											  "Wal Writer",
											  ALLOCSET_DEFAULT_SIZES);
	MemoryContextSwitchTo(walwriter_context);

	/*
	 * If an exception is encountered, processing resumes here.
	 *
	 * This code is heavily based on bgwriter.c, q.v.
	 */
	if (sigsetjmp(local_sigjmp_buf, 1) != 0)
	{
		/* Since not using PG_TRY, must reset error stack by hand */
		error_context_stack = NULL;

		/* Prevent interrupts while cleaning up */
		HOLD_INTERRUPTS();

		/* Report the error to the server log */
		EmitErrorReport();

		/*
		 * These operations are really just a minimal subset of
		 * AbortTransaction().  We don't have very many resources to worry
		 * about in walwriter, but we do have LWLocks, and perhaps buffers?
		 */
		LWLockReleaseAll();
		ConditionVariableCancelSleep();
		pgstat_report_wait_end();
		AbortBufferIO();
		UnlockBuffers();
		/* buffer pins are released here: */
		ResourceOwnerRelease(CurrentResourceOwner,
							 RESOURCE_RELEASE_BEFORE_LOCKS,
							 false, true);
		/* we needn't bother with the other ResourceOwnerRelease phases */
		AtEOXact_Buffers(false);
		AtEOXact_SMgr();
		AtEOXact_Files();
		AtEOXact_HashTables(false);

		/*
		 * Now return to normal top-level context and clear ErrorContext for
		 * next time.
		 */
		MemoryContextSwitchTo(walwriter_context);
		FlushErrorState();

		/* Flush any leaked data in the top-level context */
		MemoryContextResetAndDeleteChildren(walwriter_context);

		/* Now we can allow interrupts again */
		RESUME_INTERRUPTS();

		/*
		 * Sleep at least 1 second after any error.  A write error is likely
		 * to be repeated, and we don't want to be filling the error logs as
		 * fast as we can.
		 */
		pg_usleep(1000000L);

		/*
		 * Close all open files after any error.  This is helpful on Windows,
		 * where holding deleted files open causes various strange errors.
		 * It's not clear we need it elsewhere, but shouldn't hurt.
		 */
		smgrcloseall();
	}

	/* We can now handle ereport(ERROR) */
	PG_exception_stack = &local_sigjmp_buf;

	/*
	 * Unblock signals (they were blocked when the postmaster forked us)
	 */
	PG_SETMASK(&UnBlockSig);

	/*
	 * Reset hibernation state after any error.
	 */
	left_till_hibernate = LOOPS_UNTIL_HIBERNATE;
	hibernating = false;
	SetWalWriterSleeping(false);

	/*
	 * Advertise our latch that backends can use to wake us up while we're
	 * sleeping.
	 */
	ProcGlobal->walwriterLatch = &MyProc->procLatch;

	/*
	 * Loop forever
	 */
	for (;;)
	{
		long		cur_timeout;
		int			rc;

		/*
		 * Advertise whether we might hibernate in this cycle.  We do this
		 * before resetting the latch to ensure that any async commits will
		 * see the flag set if they might possibly need to wake us up, and
		 * that we won't miss any signal they send us.  (If we discover work
		 * to do in the last cycle before we would hibernate, the global flag
		 * will be set unnecessarily, but little harm is done.)  But avoid
		 * touching the global flag if it doesn't need to change.
		 */
		if (hibernating != (left_till_hibernate <= 1))
		{
			hibernating = (left_till_hibernate <= 1);
			SetWalWriterSleeping(hibernating);
		}

		/* Clear any already-pending wakeups */
		ResetLatch(MyLatch);

		/*
		 * Process any requests or signals received recently.
		 */
		if (got_SIGHUP)
		{
			got_SIGHUP = false;
			ProcessConfigFile(PGC_SIGHUP);
		}
		if (shutdown_requested)
		{
			/* Normal exit from the walwriter is here */
			proc_exit(0);		/* done */
		}

		/*
		 * Do what we're here for; then, if XLogBackgroundFlush() found useful
		 * work to do, reset hibernation counter.
		 */
		if (XLogBackgroundFlush())
			left_till_hibernate = LOOPS_UNTIL_HIBERNATE;
		else if (left_till_hibernate > 0)
			left_till_hibernate--;

		/*
		 * Sleep until we are signaled or WalWriterDelay has elapsed.  If we
		 * haven't done anything useful for quite some time, lengthen the
		 * sleep time so as to reduce the server's idle power consumption.
		 */
		if (left_till_hibernate > 0)
			cur_timeout = WalWriterDelay;		/* in ms */
		else
			cur_timeout = WalWriterDelay * HIBERNATE_FACTOR;

		rc = WaitLatch(MyLatch,
					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
					   cur_timeout,
					   WAIT_EVENT_WAL_WRITER_MAIN);

		/*
		 * Emergency bailout if postmaster has died.  This is to avoid the
		 * necessity for manual cleanup of all postmaster children.
		 */
		if (rc & WL_POSTMASTER_DEATH)
			exit(1);
	}
}
Beispiel #11
0
/*
 * Main entry point for bgwriter process
 *
 * This is invoked from BootstrapMain, which has already created the basic
 * execution environment, but not enabled signals yet.
 */
void
BackgroundWriterMain(void)
{
    sigjmp_buf	local_sigjmp_buf;
    MemoryContext bgwriter_context;

    am_bg_writer = true;

    /*
     * If possible, make this process a group leader, so that the postmaster
     * can signal any child processes too.	(bgwriter probably never has any
     * child processes, but for consistency we make all postmaster child
     * processes do this.)
     */
#ifdef HAVE_SETSID
    if (setsid() < 0)
        elog(FATAL, "setsid() failed: %m");
#endif

    /*
     * Properly accept or ignore signals the postmaster might send us
     *
     * SIGUSR1 is presently unused; keep it spare in case someday we want this
     * process to participate in ProcSignal signalling.
     */
    pqsignal(SIGHUP, BgSigHupHandler);	/* set flag to read config file */
    pqsignal(SIGINT, SIG_IGN);			/* as of 9.2 no longer requests checkpoint */
    pqsignal(SIGTERM, ReqShutdownHandler); 	/* shutdown */
    pqsignal(SIGQUIT, bg_quickdie);		/* hard crash time */
    pqsignal(SIGALRM, SIG_IGN);
    pqsignal(SIGPIPE, SIG_IGN);
    pqsignal(SIGUSR1, SIG_IGN);			/* reserve for ProcSignal */
    pqsignal(SIGUSR2, SIG_IGN);

    /*
     * Reset some signals that are accepted by postmaster but not here
     */
    pqsignal(SIGCHLD, SIG_DFL);
    pqsignal(SIGTTIN, SIG_DFL);
    pqsignal(SIGTTOU, SIG_DFL);
    pqsignal(SIGCONT, SIG_DFL);
    pqsignal(SIGWINCH, SIG_DFL);

    /* We allow SIGQUIT (quickdie) at all times */
    sigdelset(&BlockSig, SIGQUIT);

    /*
     * Create a resource owner to keep track of our resources (currently only
     * buffer pins).
     */
    CurrentResourceOwner = ResourceOwnerCreate(NULL, "Background Writer");

    /*
     * Create a memory context that we will do all our work in.  We do this so
     * that we can reset the context during error recovery and thereby avoid
     * possible memory leaks.  Formerly this code just ran in
     * TopMemoryContext, but resetting that would be a really bad idea.
     */
    bgwriter_context = AllocSetContextCreate(TopMemoryContext,
                       "Background Writer",
                       ALLOCSET_DEFAULT_MINSIZE,
                       ALLOCSET_DEFAULT_INITSIZE,
                       ALLOCSET_DEFAULT_MAXSIZE);
    MemoryContextSwitchTo(bgwriter_context);

    /*
     * 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)
    {
        /* Since not using PG_TRY, must reset error stack by hand */
        error_context_stack = NULL;

        /* Prevent interrupts while cleaning up */
        HOLD_INTERRUPTS();

        /* Report the error to the server log */
        EmitErrorReport();

        /*
         * These operations are really just a minimal subset of
         * AbortTransaction().	We don't have very many resources to worry
         * about in bgwriter, but we do have LWLocks, buffers, and temp files.
         */
        LWLockReleaseAll();
        AbortBufferIO();
        UnlockBuffers();
        /* buffer pins are released here: */
        ResourceOwnerRelease(CurrentResourceOwner,
                             RESOURCE_RELEASE_BEFORE_LOCKS,
                             false, true);
        /* we needn't bother with the other ResourceOwnerRelease phases */
        AtEOXact_Buffers(false);
        AtEOXact_Files();
        AtEOXact_HashTables(false);

        /*
         * Now return to normal top-level context and clear ErrorContext for
         * next time.
         */
        MemoryContextSwitchTo(bgwriter_context);
        FlushErrorState();

        /* Flush any leaked data in the top-level context */
        MemoryContextResetAndDeleteChildren(bgwriter_context);

        /* Now we can allow interrupts again */
        RESUME_INTERRUPTS();

        /*
         * Sleep at least 1 second after any error.  A write error is likely
         * to be repeated, and we don't want to be filling the error logs as
         * fast as we can.
         */
        pg_usleep(1000000L);

        /*
         * Close all open files after any error.  This is helpful on Windows,
         * where holding deleted files open causes various strange errors.
         * It's not clear we need it elsewhere, but shouldn't hurt.
         */
        smgrcloseall();
    }

    /* We can now handle ereport(ERROR) */
    PG_exception_stack = &local_sigjmp_buf;

    /*
     * Unblock signals (they were blocked when the postmaster forked us)
     */
    PG_SETMASK(&UnBlockSig);

    /*
     * Use the recovery target timeline ID during recovery
     */
    if (RecoveryInProgress())
        ThisTimeLineID = GetRecoveryTargetTLI();

    /*
     * Loop forever
     */
    for (;;)
    {
        /*
         * Emergency bailout if postmaster has died.  This is to avoid the
         * necessity for manual cleanup of all postmaster children.
         */
        if (!PostmasterIsAlive())
            exit(1);

        if (got_SIGHUP)
        {
            got_SIGHUP = false;
            ProcessConfigFile(PGC_SIGHUP);
            /* update global shmem state for sync rep */
        }
        if (shutdown_requested)
        {
            /*
             * From here on, elog(ERROR) should end with exit(1), not send
             * control back to the sigsetjmp block above
             */
            ExitOnAnyError = true;
            /* Normal exit from the bgwriter is here */
            proc_exit(0);		/* done */
        }

        /*
         * Do one cycle of dirty-buffer writing.
         */
        BgBufferSync();

        /* Nap for the configured time. */
        BgWriterNap();
    }
}
Beispiel #12
0
/*
 * Helper function for the various SQL callable logical decoding functions.
 */
static Datum
pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool binary)
{
	Name		name = PG_GETARG_NAME(0);
	XLogRecPtr	upto_lsn;
	int32		upto_nchanges;

	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
	MemoryContext per_query_ctx;
	MemoryContext oldcontext;

	XLogRecPtr	end_of_wal;
	XLogRecPtr	startptr;

	LogicalDecodingContext *ctx;

	ResourceOwner old_resowner = CurrentResourceOwner;
	ArrayType  *arr;
	Size		ndim;
	List	   *options = NIL;
	DecodingOutputState *p;

	if (PG_ARGISNULL(1))
		upto_lsn = InvalidXLogRecPtr;
	else
		upto_lsn = PG_GETARG_LSN(1);

	if (PG_ARGISNULL(2))
		upto_nchanges = InvalidXLogRecPtr;
	else
		upto_nchanges = PG_GETARG_INT32(2);

	/* check to see if caller supports us returning a tuplestore */
	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("set-valued function called in context that cannot accept a set")));
	if (!(rsinfo->allowedModes & SFRM_Materialize))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("materialize mode required, but it is not allowed in this context")));

	/* state to write output to */
	p = palloc0(sizeof(DecodingOutputState));

	p->binary_output = binary;

	/* Build a tuple descriptor for our result type */
	if (get_call_result_type(fcinfo, NULL, &p->tupdesc) != TYPEFUNC_COMPOSITE)
		elog(ERROR, "return type must be a row type");

	check_permissions();

	CheckLogicalDecodingRequirements();

	arr = PG_GETARG_ARRAYTYPE_P(3);
	ndim = ARR_NDIM(arr);

	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
	oldcontext = MemoryContextSwitchTo(per_query_ctx);

	if (ndim > 1)
	{
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("array must be one-dimensional")));
	}
	else if (array_contains_nulls(arr))
	{
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("array must not contain nulls")));
	}
	else if (ndim == 1)
	{
		int			nelems;
		Datum	   *datum_opts;
		int			i;

		Assert(ARR_ELEMTYPE(arr) == TEXTOID);

		deconstruct_array(arr, TEXTOID, -1, false, 'i',
						  &datum_opts, NULL, &nelems);

		if (nelems % 2 != 0)
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("array must have even number of elements")));

		for (i = 0; i < nelems; i += 2)
		{
			char	   *name = TextDatumGetCString(datum_opts[i]);
			char	   *opt = TextDatumGetCString(datum_opts[i + 1]);

			options = lappend(options, makeDefElem(name, (Node *) makeString(opt)));
		}
	}

	p->tupstore = tuplestore_begin_heap(true, false, work_mem);
	rsinfo->returnMode = SFRM_Materialize;
	rsinfo->setResult = p->tupstore;
	rsinfo->setDesc = p->tupdesc;

	/* compute the current end-of-wal */
	if (!RecoveryInProgress())
		end_of_wal = GetFlushRecPtr();
	else
		end_of_wal = GetXLogReplayRecPtr(NULL);

	CheckLogicalDecodingRequirements();
	ReplicationSlotAcquire(NameStr(*name));

	PG_TRY();
	{
		ctx = CreateDecodingContext(InvalidXLogRecPtr,
									options,
									logical_read_local_xlog_page,
									LogicalOutputPrepareWrite,
									LogicalOutputWrite);

		MemoryContextSwitchTo(oldcontext);

		/*
		 * Check whether the output pluggin writes textual output if that's
		 * what we need.
		 */
		if (!binary &&
			ctx->options.output_type != OUTPUT_PLUGIN_TEXTUAL_OUTPUT)
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("output plugin cannot produce binary output")));

		ctx->output_writer_private = p;

		startptr = MyReplicationSlot->data.restart_lsn;

		CurrentResourceOwner = ResourceOwnerCreate(CurrentResourceOwner, "logical decoding");

		/* invalidate non-timetravel entries */
		InvalidateSystemCaches();

		while ((startptr != InvalidXLogRecPtr && startptr < end_of_wal) ||
			   (ctx->reader->EndRecPtr && ctx->reader->EndRecPtr < end_of_wal))
		{
			XLogRecord *record;
			char	   *errm = NULL;

			record = XLogReadRecord(ctx->reader, startptr, &errm);
			if (errm)
				elog(ERROR, "%s", errm);

			startptr = InvalidXLogRecPtr;

			/*
			 * The {begin_txn,change,commit_txn}_wrapper callbacks above will
			 * store the description into our tuplestore.
			 */
			if (record != NULL)
				LogicalDecodingProcessRecord(ctx, record);

			/* check limits */
			if (upto_lsn != InvalidXLogRecPtr &&
				upto_lsn <= ctx->reader->EndRecPtr)
				break;
			if (upto_nchanges != 0 &&
				upto_nchanges <= p->returned_rows)
				break;
		}
	}
	PG_CATCH();
	{
		/* clear all timetravel entries */
		InvalidateSystemCaches();

		PG_RE_THROW();
	}
	PG_END_TRY();

	tuplestore_donestoring(tupstore);

	CurrentResourceOwner = old_resowner;

	/*
	 * Next time, start where we left off. (Hunting things, the family
	 * business..)
	 */
	if (ctx->reader->EndRecPtr != InvalidXLogRecPtr && confirm)
		LogicalConfirmReceivedLocation(ctx->reader->EndRecPtr);

	/* free context, call shutdown callback */
	FreeDecodingContext(ctx);

	ReplicationSlotRelease();
	InvalidateSystemCaches();

	return (Datum) 0;
}
Beispiel #13
0
/*
 * Main entry point for bgwriter process
 *
 * This is invoked from BootstrapMain, which has already created the basic
 * execution environment, but not enabled signals yet.
 */
void
BackgroundWriterMain(void)
{
	sigjmp_buf	local_sigjmp_buf;
	MemoryContext bgwriter_context;

	BgWriterShmem->bgwriter_pid = MyProcPid;
	am_bg_writer = true;

	/*
	 * If possible, make this process a group leader, so that the postmaster
	 * can signal any child processes too.	(bgwriter probably never has any
	 * child processes, but for consistency we make all postmaster child
	 * processes do this.)
	 */
#ifdef HAVE_SETSID
	if (setsid() < 0)
		elog(FATAL, "setsid() failed: %m");
#endif

	/*
	 * Properly accept or ignore signals the postmaster might send us
	 *
	 * Note: we deliberately ignore SIGTERM, because during a standard Unix
	 * system shutdown cycle, init will SIGTERM all processes at once.	We
	 * want to wait for the backends to exit, whereupon the postmaster will
	 * tell us it's okay to shut down (via SIGUSR2).
	 *
	 * SIGUSR1 is presently unused; keep it spare in case someday we want this
	 * process to participate in sinval messaging.
	 */
	pqsignal(SIGHUP, BgSigHupHandler);	/* set flag to read config file */
	pqsignal(SIGINT, ReqCheckpointHandler);		/* request checkpoint */
	pqsignal(SIGTERM, SIG_IGN); /* ignore SIGTERM */
	pqsignal(SIGQUIT, bg_quickdie);		/* hard crash time */
	pqsignal(SIGALRM, SIG_IGN);
	pqsignal(SIGPIPE, SIG_IGN);
	pqsignal(SIGUSR1, SIG_IGN); /* reserve for sinval */
	pqsignal(SIGUSR2, ReqShutdownHandler);		/* request shutdown */

	/*
	 * Reset some signals that are accepted by postmaster but not here
	 */
	pqsignal(SIGCHLD, SIG_DFL);
	pqsignal(SIGTTIN, SIG_DFL);
	pqsignal(SIGTTOU, SIG_DFL);
	pqsignal(SIGCONT, SIG_DFL);
	pqsignal(SIGWINCH, SIG_DFL);

	/* We allow SIGQUIT (quickdie) at all times */
#ifdef HAVE_SIGPROCMASK
	sigdelset(&BlockSig, SIGQUIT);
#else
	BlockSig &= ~(sigmask(SIGQUIT));
#endif

	/*
	 * Initialize so that first time-driven event happens at the correct time.
	 */
	last_checkpoint_time = last_xlog_switch_time = time(NULL);

	/*
	 * Create a resource owner to keep track of our resources (currently only
	 * buffer pins).
	 */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "Background Writer");

	/*
	 * Create a memory context that we will do all our work in.  We do this so
	 * that we can reset the context during error recovery and thereby avoid
	 * possible memory leaks.  Formerly this code just ran in
	 * TopMemoryContext, but resetting that would be a really bad idea.
	 */
	bgwriter_context = AllocSetContextCreate(TopMemoryContext,
											 "Background Writer",
											 ALLOCSET_DEFAULT_MINSIZE,
											 ALLOCSET_DEFAULT_INITSIZE,
											 ALLOCSET_DEFAULT_MAXSIZE);
	MemoryContextSwitchTo(bgwriter_context);

	/*
	 * 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)
	{
		/* Since not using PG_TRY, must reset error stack by hand */
		error_context_stack = NULL;

		/* Prevent interrupts while cleaning up */
		HOLD_INTERRUPTS();

		/* Report the error to the server log */
		EmitErrorReport();

		/*
		 * These operations are really just a minimal subset of
		 * AbortTransaction().	We don't have very many resources to worry
		 * about in bgwriter, but we do have LWLocks, buffers, and temp files.
		 */
		LWLockReleaseAll();
		AbortBufferIO();
		UnlockBuffers();
		/* buffer pins are released here: */
		ResourceOwnerRelease(CurrentResourceOwner,
							 RESOURCE_RELEASE_BEFORE_LOCKS,
							 false, true);
		/* we needn't bother with the other ResourceOwnerRelease phases */
		AtEOXact_Buffers(false);
		AtEOXact_Files();
		AtEOXact_HashTables(false);

		/* Warn any waiting backends that the checkpoint failed. */
		if (ckpt_active)
		{
			/* use volatile pointer to prevent code rearrangement */
			volatile BgWriterShmemStruct *bgs = BgWriterShmem;

			SpinLockAcquire(&bgs->ckpt_lck);
			bgs->ckpt_failed++;
			bgs->ckpt_done = bgs->ckpt_started;
			SpinLockRelease(&bgs->ckpt_lck);

			ckpt_active = false;
		}

		/*
		 * Now return to normal top-level context and clear ErrorContext for
		 * next time.
		 */
		MemoryContextSwitchTo(bgwriter_context);
		FlushErrorState();

		/* Flush any leaked data in the top-level context */
		MemoryContextResetAndDeleteChildren(bgwriter_context);

		/* Now we can allow interrupts again */
		RESUME_INTERRUPTS();

		/*
		 * Sleep at least 1 second after any error.  A write error is likely
		 * to be repeated, and we don't want to be filling the error logs as
		 * fast as we can.
		 */
		pg_usleep(1000000L);

		/*
		 * Close all open files after any error.  This is helpful on Windows,
		 * where holding deleted files open causes various strange errors.
		 * It's not clear we need it elsewhere, but shouldn't hurt.
		 */
		smgrcloseall();
	}

	/* We can now handle ereport(ERROR) */
	PG_exception_stack = &local_sigjmp_buf;

	/*
	 * Unblock signals (they were blocked when the postmaster forked us)
	 */
	PG_SETMASK(&UnBlockSig);

	/*
	 * Loop forever
	 */
	for (;;)
	{
		bool		do_checkpoint = false;
		int			flags = 0;
		time_t		now;
		int			elapsed_secs;

		/*
		 * Emergency bailout if postmaster has died.  This is to avoid the
		 * necessity for manual cleanup of all postmaster children.
		 */
		if (!PostmasterIsAlive(true))
			exit(1);

		/*
		 * Process any requests or signals received recently.
		 */
		AbsorbFsyncRequests();

		if (got_SIGHUP)
		{
			got_SIGHUP = false;
			ProcessConfigFile(PGC_SIGHUP);
		}
		if (checkpoint_requested)
		{
			checkpoint_requested = false;
			do_checkpoint = true;
			BgWriterStats.m_requested_checkpoints++;
		}
		if (shutdown_requested)
		{
			/*
			 * From here on, elog(ERROR) should end with exit(1), not send
			 * control back to the sigsetjmp block above
			 */
			ExitOnAnyError = true;
			/* Close down the database */
			ShutdownXLOG(0, 0);
			DumpFreeSpaceMap(0, 0);
			/* Normal exit from the bgwriter is here */
			proc_exit(0);		/* done */
		}

		/*
		 * Force a checkpoint if too much time has elapsed since the last one.
		 * Note that we count a timed checkpoint in stats only when this
		 * occurs without an external request, but we set the CAUSE_TIME flag
		 * bit even if there is also an external request.
		 */
		now = time(NULL);
		elapsed_secs = now - last_checkpoint_time;
		if (elapsed_secs >= CheckPointTimeout)
		{
			if (!do_checkpoint)
				BgWriterStats.m_timed_checkpoints++;
			do_checkpoint = true;
			flags |= CHECKPOINT_CAUSE_TIME;
		}

		/*
		 * Do a checkpoint if requested, otherwise do one cycle of
		 * dirty-buffer writing.
		 */
		if (do_checkpoint)
		{
			/* use volatile pointer to prevent code rearrangement */
			volatile BgWriterShmemStruct *bgs = BgWriterShmem;

			/*
			 * Atomically fetch the request flags to figure out what kind of a
			 * checkpoint we should perform, and increase the started-counter
			 * to acknowledge that we've started a new checkpoint.
			 */
			SpinLockAcquire(&bgs->ckpt_lck);
			flags |= bgs->ckpt_flags;
			bgs->ckpt_flags = 0;
			bgs->ckpt_started++;
			SpinLockRelease(&bgs->ckpt_lck);

			/*
			 * We will warn if (a) too soon since last checkpoint (whatever
			 * caused it) and (b) somebody set the CHECKPOINT_CAUSE_XLOG flag
			 * since the last checkpoint start.  Note in particular that this
			 * implementation will not generate warnings caused by
			 * CheckPointTimeout < CheckPointWarning.
			 */
			if ((flags & CHECKPOINT_CAUSE_XLOG) &&
				elapsed_secs < CheckPointWarning)
				ereport(LOG,
						(errmsg("checkpoints are occurring too frequently (%d seconds apart)",
								elapsed_secs),
						 errhint("Consider increasing the configuration parameter \"checkpoint_segments\".")));

			/*
			 * Initialize bgwriter-private variables used during checkpoint.
			 */
			ckpt_active = true;
			ckpt_start_recptr = GetInsertRecPtr();
			ckpt_start_time = now;
			ckpt_cached_elapsed = 0;

			/*
			 * Do the checkpoint.
			 */
			CreateCheckPoint(flags);

			/*
			 * After any checkpoint, close all smgr files.	This is so we
			 * won't hang onto smgr references to deleted files indefinitely.
			 */
			smgrcloseall();

			/*
			 * Indicate checkpoint completion to any waiting backends.
			 */
			SpinLockAcquire(&bgs->ckpt_lck);
			bgs->ckpt_done = bgs->ckpt_started;
			SpinLockRelease(&bgs->ckpt_lck);

			ckpt_active = false;

			/*
			 * Note we record the checkpoint start time not end time as
			 * last_checkpoint_time.  This is so that time-driven checkpoints
			 * happen at a predictable spacing.
			 */
			last_checkpoint_time = now;
		}
		else
			BgBufferSync();

		/* Check for archive_timeout and switch xlog files if necessary. */
		CheckArchiveTimeout();

		/* Nap for the configured time. */
		BgWriterNap();
	}
}
Beispiel #14
0
/**
 * This method is called after fork of the sweeper process. It sets up signal
 * handlers and does initialization that is required by a postgres backend.
 */
NON_EXEC_STATIC void
BackoffSweeperMain(int argc, char *argv[])
{
	sigjmp_buf	local_sigjmp_buf;

	IsUnderPostmaster = true;
	isSweeperProcess = true;

	/* Stay away from PMChildSlot */
	MyPMChildSlot = -1;

	/* reset MyProcPid */
	MyProcPid = getpid();

	/* Lose the postmaster's on-exit routines */
	on_exit_reset();

	/* Identify myself via ps */
	init_ps_display("sweeper process", "", "", "");

	SetProcessingMode(InitProcessing);

	/*
	 * Set up signal handlers.  We operate on databases much like a regular
	 * backend, so we use the same signal handling.  See equivalent code in
	 * tcop/postgres.c.
	 */
	pqsignal(SIGHUP, SIG_IGN);
	pqsignal(SIGINT, SIG_IGN);
	pqsignal(SIGALRM, SIG_IGN);
	pqsignal(SIGPIPE, SIG_IGN);
	pqsignal(SIGUSR1, SIG_IGN);

	pqsignal(SIGTERM, die);
	pqsignal(SIGQUIT, quickdie);
	pqsignal(SIGUSR2, BackoffRequestShutdown);

	pqsignal(SIGFPE, FloatExceptionHandler);
	pqsignal(SIGCHLD, SIG_DFL);

	/*
	 * Copied from bgwriter
	 */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "Sweeper process");

	/* Early initialization */
	BaseInit();

	/* See InitPostgres()... */
	InitProcess();

	SetProcessingMode(NormalProcessing);

	/*
	 * 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();

		/*
		 * 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);

	MyBackendId = InvalidBackendId;

	/* main loop */
	BackoffSweeperLoop();

	/* One iteration done, go away */
	proc_exit(0);
}
Beispiel #15
0
/*
 * Main entry point for walwriter process
 *
 * This is invoked from BootstrapMain, which has already created the basic
 * execution environment, but not enabled signals yet.
 */
void
WalWriterMain(void)
{
	sigjmp_buf	local_sigjmp_buf;
	MemoryContext walwriter_context;

	/*
	 * If possible, make this process a group leader, so that the postmaster
	 * can signal any child processes too.	(walwriter probably never has any
	 * child processes, but for consistency we make all postmaster child
	 * processes do this.)
	 */
#ifdef HAVE_SETSID
	if (setsid() < 0)
		elog(FATAL, "setsid() failed: %m");
#endif

	/*
	 * Properly accept or ignore signals the postmaster might send us
	 *
	 * We have no particular use for SIGINT at the moment, but seems
	 * reasonable to treat like SIGTERM.
	 */
	pqsignal(SIGHUP, WalSigHupHandler); /* set flag to read config file */
	pqsignal(SIGINT, WalShutdownHandler);		/* request shutdown */
	pqsignal(SIGTERM, WalShutdownHandler);		/* request shutdown */
	pqsignal(SIGQUIT, wal_quickdie);	/* hard crash time */
	pqsignal(SIGALRM, SIG_IGN);
	pqsignal(SIGPIPE, SIG_IGN);
	pqsignal(SIGUSR1, SIG_IGN); /* reserve for ProcSignal */
	pqsignal(SIGUSR2, SIG_IGN); /* not used */

	/*
	 * Reset some signals that are accepted by postmaster but not here
	 */
	pqsignal(SIGCHLD, SIG_DFL);
	pqsignal(SIGTTIN, SIG_DFL);
	pqsignal(SIGTTOU, SIG_DFL);
	pqsignal(SIGCONT, SIG_DFL);
	pqsignal(SIGWINCH, SIG_DFL);

	/* We allow SIGQUIT (quickdie) at all times */
	sigdelset(&BlockSig, SIGQUIT);

	/*
	 * Create a resource owner to keep track of our resources (not clear that
	 * we need this, but may as well have one).
	 */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "Wal Writer");

	/*
	 * Create a memory context that we will do all our work in.  We do this so
	 * that we can reset the context during error recovery and thereby avoid
	 * possible memory leaks.  Formerly this code just ran in
	 * TopMemoryContext, but resetting that would be a really bad idea.
	 */
	walwriter_context = AllocSetContextCreate(TopMemoryContext,
											  "Wal Writer",
											  ALLOCSET_DEFAULT_MINSIZE,
											  ALLOCSET_DEFAULT_INITSIZE,
											  ALLOCSET_DEFAULT_MAXSIZE);
	MemoryContextSwitchTo(walwriter_context);

	/*
	 * If an exception is encountered, processing resumes here.
	 *
	 * This code is heavily based on bgwriter.c, q.v.
	 */
	if (sigsetjmp(local_sigjmp_buf, 1) != 0)
	{
		/* Since not using PG_TRY, must reset error stack by hand */
		error_context_stack = NULL;

		/* Prevent interrupts while cleaning up */
		HOLD_INTERRUPTS();

		/* Report the error to the server log */
		EmitErrorReport();

		/*
		 * These operations are really just a minimal subset of
		 * AbortTransaction().	We don't have very many resources to worry
		 * about in walwriter, but we do have LWLocks, and perhaps buffers?
		 */
		LWLockReleaseAll();
		AbortBufferIO();
		UnlockBuffers();
		/* buffer pins are released here: */
		ResourceOwnerRelease(CurrentResourceOwner,
							 RESOURCE_RELEASE_BEFORE_LOCKS,
							 false, true);
		/* we needn't bother with the other ResourceOwnerRelease phases */
		AtEOXact_Buffers(false);
		AtEOXact_Files();
		AtEOXact_HashTables(false);

		/*
		 * Now return to normal top-level context and clear ErrorContext for
		 * next time.
		 */
		MemoryContextSwitchTo(walwriter_context);
		FlushErrorState();

		/* Flush any leaked data in the top-level context */
		MemoryContextResetAndDeleteChildren(walwriter_context);

		/* Now we can allow interrupts again */
		RESUME_INTERRUPTS();

		/*
		 * Sleep at least 1 second after any error.  A write error is likely
		 * to be repeated, and we don't want to be filling the error logs as
		 * fast as we can.
		 */
		pg_usleep(1000000L);

		/*
		 * Close all open files after any error.  This is helpful on Windows,
		 * where holding deleted files open causes various strange errors.
		 * It's not clear we need it elsewhere, but shouldn't hurt.
		 */
		smgrcloseall();
	}

	/* We can now handle ereport(ERROR) */
	PG_exception_stack = &local_sigjmp_buf;

	/*
	 * Unblock signals (they were blocked when the postmaster forked us)
	 */
	PG_SETMASK(&UnBlockSig);

	/*
	 * Loop forever
	 */
	for (;;)
	{
		long		udelay;

		/*
		 * Emergency bailout if postmaster has died.  This is to avoid the
		 * necessity for manual cleanup of all postmaster children.
		 */
		if (!PostmasterIsAlive(true))
			exit(1);

		/*
		 * Process any requests or signals received recently.
		 */
		if (got_SIGHUP)
		{
			got_SIGHUP = false;
			ProcessConfigFile(PGC_SIGHUP);
		}
		if (shutdown_requested)
		{
			/* Normal exit from the walwriter is here */
			proc_exit(0);		/* done */
		}

		/*
		 * Do what we're here for...
		 */
		XLogBackgroundFlush();

		/*
		 * Delay until time to do something more, but fall out of delay
		 * reasonably quickly if signaled.
		 */
		udelay = WalWriterDelay * 1000L;
		while (udelay > 999999L)
		{
			if (got_SIGHUP || shutdown_requested)
				break;
			pg_usleep(1000000L);
			udelay -= 1000000L;
		}
		if (!(got_SIGHUP || shutdown_requested))
			pg_usleep(udelay);
	}
}
Beispiel #16
0
/*
 * Background worker entrypoint.
 *
 * This is intended to demonstrate how a background worker can be used to
 * facilitate a parallel computation.  Most of the logic here is fairly
 * boilerplate stuff, designed to attach to the shared memory segment,
 * notify the user backend that we're alive, and so on.  The
 * application-specific bits of logic that you'd replace for your own worker
 * are attach_to_queues() and copy_messages().
 */
void
test_shm_mq_main(Datum main_arg)
{
	dsm_segment *seg;
	shm_toc    *toc;
	shm_mq_handle *inqh;
	shm_mq_handle *outqh;
	volatile test_shm_mq_header *hdr;
	int			myworkernumber;
	PGPROC	   *registrant;

	/*
	 * Establish signal handlers.
	 *
	 * We want CHECK_FOR_INTERRUPTS() to kill off this worker process just as
	 * it would a normal user backend.  To make that happen, we establish a
	 * signal handler that is a stripped-down version of die().  We don't have
	 * any equivalent of the backend's command-read loop, where interrupts can
	 * be processed immediately, so make sure ImmediateInterruptOK is turned
	 * off.
	 */
	pqsignal(SIGTERM, handle_sigterm);
	ImmediateInterruptOK = false;
	BackgroundWorkerUnblockSignals();

	/*
	 * Connect to the dynamic shared memory segment.
	 *
	 * The backend that registered this worker passed us the ID of a shared
	 * memory segment to which we must attach for further instructions.  In
	 * order to attach to dynamic shared memory, we need a resource owner.
	 * Once we've mapped the segment in our address space, attach to the table
	 * of contents so we can locate the various data structures we'll need to
	 * find within the segment.
	 */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "test_shm_mq worker");
	seg = dsm_attach(DatumGetInt32(main_arg));
	if (seg == NULL)
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("unable to map dynamic shared memory segment")));
	toc = shm_toc_attach(PG_TEST_SHM_MQ_MAGIC, dsm_segment_address(seg));
	if (toc == NULL)
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
			   errmsg("bad magic number in dynamic shared memory segment")));

	/*
	 * Acquire a worker number.
	 *
	 * By convention, the process registering this background worker should
	 * have stored the control structure at key 0.  We look up that key to
	 * find it.  Our worker number gives our identity: there may be just one
	 * worker involved in this parallel operation, or there may be many.
	 */
	hdr = shm_toc_lookup(toc, 0);
	SpinLockAcquire(&hdr->mutex);
	myworkernumber = ++hdr->workers_attached;
	SpinLockRelease(&hdr->mutex);
	if (myworkernumber > hdr->workers_total)
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("too many message queue testing workers already")));

	/*
	 * Attach to the appropriate message queues.
	 */
	attach_to_queues(seg, toc, myworkernumber, &inqh, &outqh);

	/*
	 * Indicate that we're fully initialized and ready to begin the main part
	 * of the parallel operation.
	 *
	 * Once we signal that we're ready, the user backend is entitled to assume
	 * that our on_dsm_detach callbacks will fire before we disconnect from
	 * the shared memory segment and exit.  Generally, that means we must have
	 * attached to all relevant dynamic shared memory data structures by now.
	 */
	SpinLockAcquire(&hdr->mutex);
	++hdr->workers_ready;
	SpinLockRelease(&hdr->mutex);
	registrant = BackendPidGetProc(MyBgworkerEntry->bgw_notify_pid);
	if (registrant == NULL)
	{
		elog(DEBUG1, "registrant backend has exited prematurely");
		proc_exit(1);
	}
	SetLatch(&registrant->procLatch);

	/* Do the work. */
	copy_messages(inqh, outqh);

	/*
	 * We're done.  Explicitly detach the shared memory segment so that we
	 * don't get a resource leak warning at commit time.  This will fire any
	 * on_dsm_detach callbacks we've registered, as well.  Once that's done,
	 * we can go ahead and exit.
	 */
	dsm_detach(seg);
	proc_exit(1);
}
Beispiel #17
0
void
worker_test_main(Datum main_arg)
{
	dsm_segment *seg;
	volatile test_shm_mq_header *hdr;
	PGPROC *registrant;

	pqsignal(SIGHUP,  handle_sighup);
	pqsignal(SIGTERM, handle_sigterm);

	BackgroundWorkerUnblockSignals();

	printf("worker_test_main: %d\n", DatumGetInt32(main_arg));

	CurrentResourceOwner = ResourceOwnerCreate(NULL, "worker test");

	seg = dsm_attach(DatumGetInt32(main_arg));

	if (seg == NULL)
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("unable to map dynamic shared memory segment")));

	hdr = dsm_segment_address(seg);

	/* 開始 */
	SpinLockAcquire(&hdr->mutex);
	hdr->workers_ready++;
	hdr->workers_attached++;
	SpinLockRelease(&hdr->mutex);

	registrant = BackendPidGetProc(MyBgworkerEntry->bgw_notify_pid);
	if (registrant == NULL)
	{
		elog(DEBUG1, "registrant backend has exited prematurely");
		proc_exit(1);
	}
	SetLatch(&registrant->procLatch);

	/* Do the work */

	BackgroundWorkerInitializeConnection(hdr->dbname, NULL);

	printf("DSM: %p\n", dsm_segment_address);

#if 0
	SetCurrentStatementStartTimestamp();
	StartTransactionCommand();
	SPI_connect();
	PushActiveSnapshot(GetTransactionSnapshot());
	pgstat_report_activity(STATE_RUNNING, "initializing spi_worker schema");	

	SPI_finish();
	PopActiveSnapshot();
	CommitTransactionCommand();
	pgstat_report_activity(STATE_IDLE, NULL);
#endif

	dsm_detach(seg);

	proc_exit(0);
}
Beispiel #18
0
/*
 * Helper function for the various SQL callable logical decoding functions.
 */
static Datum
pg_logical_slot_get_changes_guts(FunctionCallInfo fcinfo, bool confirm, bool binary)
{
	Name		name;
	XLogRecPtr	upto_lsn;
	int32		upto_nchanges;
	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
	MemoryContext per_query_ctx;
	MemoryContext oldcontext;
	XLogRecPtr	end_of_wal;
	XLogRecPtr	startptr;
	LogicalDecodingContext *ctx;
	ResourceOwner old_resowner = CurrentResourceOwner;
	ArrayType  *arr;
	Size		ndim;
	List	   *options = NIL;
	DecodingOutputState *p;

	check_permissions();

	CheckLogicalDecodingRequirements();

	if (PG_ARGISNULL(0))
		ereport(ERROR,
				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
				 errmsg("slot name must not be null")));
	name = PG_GETARG_NAME(0);

	if (PG_ARGISNULL(1))
		upto_lsn = InvalidXLogRecPtr;
	else
		upto_lsn = PG_GETARG_LSN(1);

	if (PG_ARGISNULL(2))
		upto_nchanges = InvalidXLogRecPtr;
	else
		upto_nchanges = PG_GETARG_INT32(2);

	if (PG_ARGISNULL(3))
		ereport(ERROR,
				(errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
				 errmsg("options array must not be null")));
	arr = PG_GETARG_ARRAYTYPE_P(3);

	/* check to see if caller supports us returning a tuplestore */
	if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("set-valued function called in context that cannot accept a set")));
	if (!(rsinfo->allowedModes & SFRM_Materialize))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("materialize mode required, but it is not allowed in this context")));

	/* state to write output to */
	p = palloc0(sizeof(DecodingOutputState));

	p->binary_output = binary;

	/* Build a tuple descriptor for our result type */
	if (get_call_result_type(fcinfo, NULL, &p->tupdesc) != TYPEFUNC_COMPOSITE)
		elog(ERROR, "return type must be a row type");

	per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
	oldcontext = MemoryContextSwitchTo(per_query_ctx);

	/* Deconstruct options array */
	ndim = ARR_NDIM(arr);
	if (ndim > 1)
	{
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("array must be one-dimensional")));
	}
	else if (array_contains_nulls(arr))
	{
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("array must not contain nulls")));
	}
	else if (ndim == 1)
	{
		int			nelems;
		Datum	   *datum_opts;
		int			i;

		Assert(ARR_ELEMTYPE(arr) == TEXTOID);

		deconstruct_array(arr, TEXTOID, -1, false, 'i',
						  &datum_opts, NULL, &nelems);

		if (nelems % 2 != 0)
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("array must have even number of elements")));

		for (i = 0; i < nelems; i += 2)
		{
			char	   *name = TextDatumGetCString(datum_opts[i]);
			char	   *opt = TextDatumGetCString(datum_opts[i + 1]);

			options = lappend(options, makeDefElem(name, (Node *) makeString(opt), -1));
		}
	}

	p->tupstore = tuplestore_begin_heap(true, false, work_mem);
	rsinfo->returnMode = SFRM_Materialize;
	rsinfo->setResult = p->tupstore;
	rsinfo->setDesc = p->tupdesc;

	/*
	 * Compute the current end-of-wal and maintain ThisTimeLineID.
	 * RecoveryInProgress() will update ThisTimeLineID on promotion.
	 */
	if (!RecoveryInProgress())
		end_of_wal = GetFlushRecPtr();
	else
		end_of_wal = GetXLogReplayRecPtr(&ThisTimeLineID);

	ReplicationSlotAcquire(NameStr(*name), true);

	PG_TRY();
	{
		/* restart at slot's confirmed_flush */
		ctx = CreateDecodingContext(InvalidXLogRecPtr,
									options,
									false,
									logical_read_local_xlog_page,
									LogicalOutputPrepareWrite,
									LogicalOutputWrite, NULL);

		MemoryContextSwitchTo(oldcontext);

		/*
		 * Check whether the output plugin writes textual output if that's
		 * what we need.
		 */
		if (!binary &&
			ctx->options.output_type !=OUTPUT_PLUGIN_TEXTUAL_OUTPUT)
			ereport(ERROR,
					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
					 errmsg("logical decoding output plugin \"%s\" produces binary output, but function \"%s\" expects textual data",
							NameStr(MyReplicationSlot->data.plugin),
							format_procedure(fcinfo->flinfo->fn_oid))));

		ctx->output_writer_private = p;

		/*
		 * Decoding of WAL must start at restart_lsn so that the entirety of
		 * xacts that committed after the slot's confirmed_flush can be
		 * accumulated into reorder buffers.
		 */
		startptr = MyReplicationSlot->data.restart_lsn;

		CurrentResourceOwner = ResourceOwnerCreate(CurrentResourceOwner, "logical decoding");

		/* invalidate non-timetravel entries */
		InvalidateSystemCaches();

		/* Decode until we run out of records */
		while ((startptr != InvalidXLogRecPtr && startptr < end_of_wal) ||
			   (ctx->reader->EndRecPtr != InvalidXLogRecPtr && ctx->reader->EndRecPtr < end_of_wal))
		{
			XLogRecord *record;
			char	   *errm = NULL;

			record = XLogReadRecord(ctx->reader, startptr, &errm);
			if (errm)
				elog(ERROR, "%s", errm);

			/*
			 * Now that we've set up the xlog reader state, subsequent calls
			 * pass InvalidXLogRecPtr to say "continue from last record"
			 */
			startptr = InvalidXLogRecPtr;

			/*
			 * The {begin_txn,change,commit_txn}_wrapper callbacks above will
			 * store the description into our tuplestore.
			 */
			if (record != NULL)
				LogicalDecodingProcessRecord(ctx, ctx->reader);

			/* check limits */
			if (upto_lsn != InvalidXLogRecPtr &&
				upto_lsn <= ctx->reader->EndRecPtr)
				break;
			if (upto_nchanges != 0 &&
				upto_nchanges <= p->returned_rows)
				break;
			CHECK_FOR_INTERRUPTS();
		}

		tuplestore_donestoring(tupstore);

		CurrentResourceOwner = old_resowner;

		/*
		 * Next time, start where we left off. (Hunting things, the family
		 * business..)
		 */
		if (ctx->reader->EndRecPtr != InvalidXLogRecPtr && confirm)
		{
			LogicalConfirmReceivedLocation(ctx->reader->EndRecPtr);

			/*
			 * If only the confirmed_flush_lsn has changed the slot won't get
			 * marked as dirty by the above. Callers on the walsender
			 * interface are expected to keep track of their own progress and
			 * don't need it written out. But SQL-interface users cannot
			 * specify their own start positions and it's harder for them to
			 * keep track of their progress, so we should make more of an
			 * effort to save it for them.
			 *
			 * Dirty the slot so it's written out at the next checkpoint.
			 * We'll still lose its position on crash, as documented, but it's
			 * better than always losing the position even on clean restart.
			 */
			ReplicationSlotMarkDirty();
		}

		/* free context, call shutdown callback */
		FreeDecodingContext(ctx);

		ReplicationSlotRelease();
		InvalidateSystemCaches();
	}
	PG_CATCH();
	{
		/* clear all timetravel entries */
		InvalidateSystemCaches();

		PG_RE_THROW();
	}
	PG_END_TRY();

	return (Datum) 0;
}
Beispiel #19
0
void 
InitResQueues(void)
{

	HeapTuple			tuple;
	int					numQueues = 0;
	bool				queuesok = true;
	cqContext		   *pcqCtx;
	cqContext			cqc;
	
	Assert(ResScheduler);

	/*
	 * Need a resource owner to keep the heapam code happy.
	 */
	Assert(CurrentResourceOwner == NULL);

	ResourceOwner owner = ResourceOwnerCreate(NULL, "InitQueues");
	CurrentResourceOwner = owner;
	
	/**
	 * The resqueue shared mem initialization must be serialized. Only the first session
	 * should do the init.
	 * Serialization is done the ResQueueLock LW_EXCLUSIVE. However, we must obtain all DB
	 * lock before obtaining LWlock.
	 * So, we must have obtained ResQueueRelationId and ResQueueCapabilityRelationId lock
	 * first.
	 */
	Relation relResqueue = heap_open(ResQueueRelationId, AccessShareLock);
	LockRelationOid(ResQueueCapabilityRelationId, RowExclusiveLock);
	LWLockAcquire(ResQueueLock, LW_EXCLUSIVE);

	if (ResScheduler->num_queues > 0)
	{
		/* Hash table has already been loaded */
		LWLockRelease(ResQueueLock);
		UnlockRelationOid(ResQueueCapabilityRelationId, RowExclusiveLock);
		heap_close(relResqueue, AccessShareLock);
		CurrentResourceOwner = NULL;
		ResourceOwnerDelete(owner);
		return;
	}

	/* XXX XXX: should this be rowexclusive ? */
	pcqCtx = caql_beginscan(
			caql_indexOK(
					caql_addrel(cqclr(&cqc), relResqueue),
					false),
			cql("SELECT * FROM pg_resqueue ", NULL));

	while (HeapTupleIsValid(tuple = caql_getnext(pcqCtx)))
	{
		Form_pg_resqueue	queueform;
		Oid					queueid;
		bool				overcommit;
		float4				ignorelimit;
		Cost				thresholds[NUM_RES_LIMIT_TYPES];
		char				*queuename;

		numQueues++;

		queueform = (Form_pg_resqueue) GETSTRUCT(tuple);

		queueid = HeapTupleGetOid(tuple);
		queuename = NameStr(queueform->rsqname);
		thresholds[RES_COUNT_LIMIT] = queueform->rsqcountlimit;
		thresholds[RES_COST_LIMIT] = queueform->rsqcostlimit;

		thresholds[RES_MEMORY_LIMIT] = ResourceQueueGetMemoryLimit(queueid);
		overcommit = queueform->rsqovercommit;
		ignorelimit = queueform->rsqignorecostlimit;
		queuesok = ResCreateQueue(queueid, thresholds, overcommit, ignorelimit);

		if (!queuesok)
		{
			/** Break out of loop. Close relations, relinquish LWLock and then error out */ 
			break;
		}
	}

	caql_endscan(pcqCtx);
	LWLockRelease(ResQueueLock);
	UnlockRelationOid(ResQueueCapabilityRelationId, RowExclusiveLock);
	heap_close(relResqueue, AccessShareLock);

	if (!queuesok)
		ereport(PANIC,
			(errcode(ERRCODE_INSUFFICIENT_RESOURCES),
			 errmsg("insufficient resource queues available"),
		errhint("Increase max_resource_queues to %d.", numQueues)));


	elog(LOG,"initialized %d resource queues", numQueues);

	CurrentResourceOwner = NULL;
	ResourceOwnerDelete(owner);

	return;
}
Beispiel #20
0
/* Main entry point for walreceiver process */
void
WalReceiverMain(void)
{
	char		conninfo[MAXCONNINFO];
	XLogRecPtr	startpoint;

	/* use volatile pointer to prevent code rearrangement */
	volatile WalRcvData *walrcv = WalRcv;

	am_walreceiver = true;

	/*
	 * WalRcv should be set up already (if we are a backend, we inherit this
	 * by fork() or EXEC_BACKEND mechanism from the postmaster).
	 */
	Assert(walrcv != NULL);

	/*
	 * Mark walreceiver as running in shared memory.
	 *
	 * Do this as early as possible, so that if we fail later on, we'll set
	 * state to STOPPED. If we die before this, the startup process will keep
	 * waiting for us to start up, until it times out.
	 */
	SpinLockAcquire(&walrcv->mutex);
	Assert(walrcv->pid == 0);
	switch (walrcv->walRcvState)
	{
		case WALRCV_STOPPING:
			/* If we've already been requested to stop, don't start up. */
			walrcv->walRcvState = WALRCV_STOPPED;
			/* fall through */

		case WALRCV_STOPPED:
			SpinLockRelease(&walrcv->mutex);
			proc_exit(1);
			break;

		case WALRCV_STARTING:
			/* The usual case */
			break;

		case WALRCV_RUNNING:
			/* Shouldn't happen */
			elog(PANIC, "walreceiver still running according to shared memory state");
	}
	/* Advertise our PID so that the startup process can kill us */
	walrcv->pid = MyProcPid;
	walrcv->walRcvState = WALRCV_RUNNING;

	/* Fetch information required to start streaming */
	strlcpy(conninfo, (char *) walrcv->conninfo, MAXCONNINFO);
	startpoint = walrcv->receivedUpto;
	SpinLockRelease(&walrcv->mutex);

	/* Arrange to clean up at walreceiver exit */
	on_shmem_exit(WalRcvDie, 0);

	/*
	 * If possible, make this process a group leader, so that the postmaster
	 * can signal any child processes too.	(walreceiver probably never has
	 * any child processes, but for consistency we make all postmaster child
	 * processes do this.)
	 */
#ifdef HAVE_SETSID
	if (setsid() < 0)
		elog(FATAL, "setsid() failed: %m");
#endif

	/* Properly accept or ignore signals the postmaster might send us */
	pqsignal(SIGHUP, WalRcvSigHupHandler);		/* set flag to read config
												 * file */
	pqsignal(SIGINT, SIG_IGN);
	pqsignal(SIGTERM, WalRcvShutdownHandler);	/* request shutdown */
	pqsignal(SIGQUIT, WalRcvQuickDieHandler);	/* hard crash time */
	pqsignal(SIGALRM, SIG_IGN);
	pqsignal(SIGPIPE, SIG_IGN);
	pqsignal(SIGUSR1, SIG_IGN);
	pqsignal(SIGUSR2, SIG_IGN);

	/* Reset some signals that are accepted by postmaster but not here */
	pqsignal(SIGCHLD, SIG_DFL);
	pqsignal(SIGTTIN, SIG_DFL);
	pqsignal(SIGTTOU, SIG_DFL);
	pqsignal(SIGCONT, SIG_DFL);
	pqsignal(SIGWINCH, SIG_DFL);

	/* We allow SIGQUIT (quickdie) at all times */
	sigdelset(&BlockSig, SIGQUIT);

	/* Load the libpq-specific functions */
	load_file("libpqwalreceiver", false);
	if (walrcv_connect == NULL || walrcv_receive == NULL ||
		walrcv_disconnect == NULL)
		elog(ERROR, "libpqwalreceiver didn't initialize correctly");

	/*
	 * Create a resource owner to keep track of our resources (not clear that
	 * we need this, but may as well have one).
	 */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "Wal Receiver");

	/* Unblock signals (they were blocked when the postmaster forked us) */
	PG_SETMASK(&UnBlockSig);

	/* Establish the connection to the primary for XLOG streaming */
	EnableWalRcvImmediateExit();
	walrcv_connect(conninfo, startpoint);
	DisableWalRcvImmediateExit();

	/* Loop until end-of-streaming or error */
	for (;;)
	{
		unsigned char type;
		char	   *buf;
		int			len;

		/*
		 * Emergency bailout if postmaster has died.  This is to avoid the
		 * necessity for manual cleanup of all postmaster children.
		 */
		if (!PostmasterIsAlive(true))
			exit(1);

		/*
		 * Exit walreceiver if we're not in recovery. This should not happen,
		 * but cross-check the status here.
		 */
		if (!RecoveryInProgress())
			ereport(FATAL,
					(errmsg("cannot continue WAL streaming, recovery has already ended")));

		/* Process any requests or signals received recently */
		ProcessWalRcvInterrupts();

		if (got_SIGHUP)
		{
			got_SIGHUP = false;
			ProcessConfigFile(PGC_SIGHUP);
		}

		/* Wait a while for data to arrive */
		if (walrcv_receive(NAPTIME_PER_CYCLE, &type, &buf, &len))
		{
			/* Accept the received data, and process it */
			XLogWalRcvProcessMsg(type, buf, len);

			/* Receive any more data we can without sleeping */
			while (walrcv_receive(0, &type, &buf, &len))
				XLogWalRcvProcessMsg(type, buf, len);

			/*
			 * If we've written some records, flush them to disk and let the
			 * startup process know about them.
			 */
			XLogWalRcvFlush();
		}
	}
}
Beispiel #21
0
/*
 * Main entry point for bgwriter process
 *
 * This is invoked from AuxiliaryProcessMain, which has already created the
 * basic execution environment, but not enabled signals yet.
 */
void
BackgroundWriterMain(void)
{
	sigjmp_buf	local_sigjmp_buf;
	MemoryContext bgwriter_context;
	bool		prev_hibernate;

	/*
	 * Properly accept or ignore signals the postmaster might send us.
	 *
	 * bgwriter doesn't participate in ProcSignal signalling, but a SIGUSR1
	 * handler is still needed for latch wakeups.
	 */
	pqsignal(SIGHUP, BgSigHupHandler);	/* set flag to read config file */
	pqsignal(SIGINT, SIG_IGN);
	pqsignal(SIGTERM, ReqShutdownHandler);		/* shutdown */
	pqsignal(SIGQUIT, bg_quickdie);		/* hard crash time */
	pqsignal(SIGALRM, SIG_IGN);
	pqsignal(SIGPIPE, SIG_IGN);
	pqsignal(SIGUSR1, bgwriter_sigusr1_handler);
	pqsignal(SIGUSR2, SIG_IGN);

	/*
	 * Reset some signals that are accepted by postmaster but not here
	 */
	pqsignal(SIGCHLD, SIG_DFL);
	pqsignal(SIGTTIN, SIG_DFL);
	pqsignal(SIGTTOU, SIG_DFL);
	pqsignal(SIGCONT, SIG_DFL);
	pqsignal(SIGWINCH, SIG_DFL);

	/* We allow SIGQUIT (quickdie) at all times */
	sigdelset(&BlockSig, SIGQUIT);

	/*
	 * Create a resource owner to keep track of our resources (currently only
	 * buffer pins).
	 */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "Background Writer");

	/*
	 * We just started, assume there has been either a shutdown or
	 * end-of-recovery snapshot.
	 */
	last_snapshot_ts = GetCurrentTimestamp();

	/*
	 * Create a memory context that we will do all our work in.  We do this so
	 * that we can reset the context during error recovery and thereby avoid
	 * possible memory leaks.  Formerly this code just ran in
	 * TopMemoryContext, but resetting that would be a really bad idea.
	 */
	bgwriter_context = AllocSetContextCreate(TopMemoryContext,
											 "Background Writer",
											 ALLOCSET_DEFAULT_MINSIZE,
											 ALLOCSET_DEFAULT_INITSIZE,
											 ALLOCSET_DEFAULT_MAXSIZE);
	MemoryContextSwitchTo(bgwriter_context);

	/*
	 * 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)
	{
		/* Since not using PG_TRY, must reset error stack by hand */
		error_context_stack = NULL;

		/* Prevent interrupts while cleaning up */
		HOLD_INTERRUPTS();

		/* Report the error to the server log */
		EmitErrorReport();

		/*
		 * These operations are really just a minimal subset of
		 * AbortTransaction().  We don't have very many resources to worry
		 * about in bgwriter, but we do have LWLocks, buffers, and temp files.
		 */
		LWLockReleaseAll();
		AbortBufferIO();
		UnlockBuffers();
		/* buffer pins are released here: */
		ResourceOwnerRelease(CurrentResourceOwner,
							 RESOURCE_RELEASE_BEFORE_LOCKS,
							 false, true);
		/* we needn't bother with the other ResourceOwnerRelease phases */
		AtEOXact_Buffers(false);
		AtEOXact_SMgr();
		AtEOXact_Files();
		AtEOXact_HashTables(false);

		/*
		 * Now return to normal top-level context and clear ErrorContext for
		 * next time.
		 */
		MemoryContextSwitchTo(bgwriter_context);
		FlushErrorState();

		/* Flush any leaked data in the top-level context */
		MemoryContextResetAndDeleteChildren(bgwriter_context);

		/* Now we can allow interrupts again */
		RESUME_INTERRUPTS();

		/*
		 * Sleep at least 1 second after any error.  A write error is likely
		 * to be repeated, and we don't want to be filling the error logs as
		 * fast as we can.
		 */
		pg_usleep(1000000L);

		/*
		 * Close all open files after any error.  This is helpful on Windows,
		 * where holding deleted files open causes various strange errors.
		 * It's not clear we need it elsewhere, but shouldn't hurt.
		 */
		smgrcloseall();

		/* Report wait end here, when there is no further possibility of wait */
		pgstat_report_wait_end();
	}

	/* We can now handle ereport(ERROR) */
	PG_exception_stack = &local_sigjmp_buf;

	/*
	 * Unblock signals (they were blocked when the postmaster forked us)
	 */
	PG_SETMASK(&UnBlockSig);

	/*
	 * Reset hibernation state after any error.
	 */
	prev_hibernate = false;

	/*
	 * Loop forever
	 */
	for (;;)
	{
		bool		can_hibernate;
		int			rc;

		/* Clear any already-pending wakeups */
		ResetLatch(MyLatch);

		if (got_SIGHUP)
		{
			got_SIGHUP = false;
			ProcessConfigFile(PGC_SIGHUP);
		}
		if (shutdown_requested)
		{
			/*
			 * From here on, elog(ERROR) should end with exit(1), not send
			 * control back to the sigsetjmp block above
			 */
			ExitOnAnyError = true;
			/* Normal exit from the bgwriter is here */
			proc_exit(0);		/* done */
		}

		/*
		 * Do one cycle of dirty-buffer writing.
		 */
		can_hibernate = BgBufferSync();

		/*
		 * Send off activity statistics to the stats collector
		 */
		pgstat_send_bgwriter();

		if (FirstCallSinceLastCheckpoint())
		{
			/*
			 * After any checkpoint, close all smgr files.  This is so we
			 * won't hang onto smgr references to deleted files indefinitely.
			 */
			smgrcloseall();
		}

		/*
		 * Log a new xl_running_xacts every now and then so replication can
		 * get into a consistent state faster (think of suboverflowed
		 * snapshots) and clean up resources (locks, KnownXids*) more
		 * frequently. The costs of this are relatively low, so doing it 4
		 * times (LOG_SNAPSHOT_INTERVAL_MS) a minute seems fine.
		 *
		 * We assume the interval for writing xl_running_xacts is
		 * significantly bigger than BgWriterDelay, so we don't complicate the
		 * overall timeout handling but just assume we're going to get called
		 * often enough even if hibernation mode is active. It's not that
		 * important that log_snap_interval_ms is met strictly. To make sure
		 * we're not waking the disk up unnecessarily on an idle system we
		 * check whether there has been any WAL inserted since the last time
		 * we've logged a running xacts.
		 *
		 * We do this logging in the bgwriter as its the only process that is
		 * run regularly and returns to its mainloop all the time. E.g.
		 * Checkpointer, when active, is barely ever in its mainloop and thus
		 * makes it hard to log regularly.
		 */
		if (XLogStandbyInfoActive() && !RecoveryInProgress())
		{
			TimestampTz timeout = 0;
			TimestampTz now = GetCurrentTimestamp();

			timeout = TimestampTzPlusMilliseconds(last_snapshot_ts,
												  LOG_SNAPSHOT_INTERVAL_MS);

			/*
			 * only log if enough time has passed and some xlog record has
			 * been inserted.
			 */
			if (now >= timeout &&
				last_snapshot_lsn != GetXLogInsertRecPtr())
			{
				last_snapshot_lsn = LogStandbySnapshot();
				last_snapshot_ts = now;
			}
		}

		/*
		 * Sleep until we are signaled or BgWriterDelay has elapsed.
		 *
		 * Note: the feedback control loop in BgBufferSync() expects that we
		 * will call it every BgWriterDelay msec.  While it's not critical for
		 * correctness that that be exact, the feedback loop might misbehave
		 * if we stray too far from that.  Hence, avoid loading this process
		 * down with latch events that are likely to happen frequently during
		 * normal operation.
		 */
		rc = WaitLatch(MyLatch,
					   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
					   BgWriterDelay /* ms */ );

		/*
		 * If no latch event and BgBufferSync says nothing's happening, extend
		 * the sleep in "hibernation" mode, where we sleep for much longer
		 * than bgwriter_delay says.  Fewer wakeups save electricity.  When a
		 * backend starts using buffers again, it will wake us up by setting
		 * our latch.  Because the extra sleep will persist only as long as no
		 * buffer allocations happen, this should not distort the behavior of
		 * BgBufferSync's control loop too badly; essentially, it will think
		 * that the system-wide idle interval didn't exist.
		 *
		 * There is a race condition here, in that a backend might allocate a
		 * buffer between the time BgBufferSync saw the alloc count as zero
		 * and the time we call StrategyNotifyBgWriter.  While it's not
		 * critical that we not hibernate anyway, we try to reduce the odds of
		 * that by only hibernating when BgBufferSync says nothing's happening
		 * for two consecutive cycles.  Also, we mitigate any possible
		 * consequences of a missed wakeup by not hibernating forever.
		 */
		if (rc == WL_TIMEOUT && can_hibernate && prev_hibernate)
		{
			/* Ask for notification at next buffer allocation */
			StrategyNotifyBgWriter(MyProc->pgprocno);
			/* Sleep ... */
			rc = WaitLatch(MyLatch,
						   WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
						   BgWriterDelay * HIBERNATE_FACTOR);
			/* Reset the notification request in case we timed out */
			StrategyNotifyBgWriter(-1);
		}

		/*
		 * Emergency bailout if postmaster has died.  This is to avoid the
		 * necessity for manual cleanup of all postmaster children.
		 */
		if (rc & WL_POSTMASTER_DEATH)
			exit(1);

		prev_hibernate = can_hibernate;
	}
}
Beispiel #22
0
/*
 * ContinuousQueryWorkerStartup
 *
 * Launches a CQ worker, which continuously generates partial query results to send
 * back to the combiner process.
 */
void
ContinuousQueryWorkerRun(Portal portal, ContinuousViewState *state, QueryDesc *queryDesc, ResourceOwner owner)
{
	EState	   *estate = NULL;
	DestReceiver *dest;
	CmdType		operation;
	MemoryContext oldcontext;
	int timeoutms = state->maxwaitms;
	MemoryContext runcontext;
	CQProcEntry *entry = GetCQProcEntry(MyCQId);
	ResourceOwner cqowner = ResourceOwnerCreate(NULL, "CQResourceOwner");
	bool savereadonly = XactReadOnly;

	cq_stat_initialize(state->viewid, MyProcPid);

	dest = CreateDestReceiver(DestCombiner);
	SetCombinerDestReceiverParams(dest, MyCQId);

	/* workers only need read-only transactions */
	XactReadOnly = true;

	runcontext = AllocSetContextCreate(TopMemoryContext, "CQRunContext",
			ALLOCSET_DEFAULT_MINSIZE,
			ALLOCSET_DEFAULT_INITSIZE,
			ALLOCSET_DEFAULT_MAXSIZE);

	elog(LOG, "\"%s\" worker %d running", queryDesc->plannedstmt->cq_target->relname, MyProcPid);
	MarkWorkerAsRunning(MyCQId, MyWorkerId);
	pgstat_report_activity(STATE_RUNNING, queryDesc->sourceText);

	TupleBufferInitLatch(WorkerTupleBuffer, MyCQId, MyWorkerId, &MyProc->procLatch);

	oldcontext = MemoryContextSwitchTo(runcontext);

retry:
	PG_TRY();
	{
		bool xact_commit = true;
		TimestampTz last_process = GetCurrentTimestamp();
		TimestampTz last_commit = GetCurrentTimestamp();

		start_executor(queryDesc, runcontext, cqowner);

		CurrentResourceOwner = cqowner;

		estate = queryDesc->estate;
		operation = queryDesc->operation;

		/*
		 * Initialize context that lives for the duration of a single iteration
		 * of the main worker loop
		 */
		CQExecutionContext = AllocSetContextCreate(estate->es_query_cxt, "CQExecutionContext",
				ALLOCSET_DEFAULT_MINSIZE,
				ALLOCSET_DEFAULT_INITSIZE,
				ALLOCSET_DEFAULT_MAXSIZE);

		estate->es_lastoid = InvalidOid;

		/*
		 * Startup combiner receiver
		 */
		(*dest->rStartup) (dest, operation, queryDesc->tupDesc);

		for (;;)
		{
			if (!TupleBufferHasUnreadSlots())
			{
				if (TimestampDifferenceExceeds(last_process, GetCurrentTimestamp(), state->emptysleepms))
				{
					/* force stats flush */
					cq_stat_report(true);

					pgstat_report_activity(STATE_IDLE, queryDesc->sourceText);
					TupleBufferWait(WorkerTupleBuffer, MyCQId, MyWorkerId);
					pgstat_report_activity(STATE_RUNNING, queryDesc->sourceText);
				}
				else
					pg_usleep(Min(WAIT_SLEEP_MS, state->emptysleepms) * 1000);
			}

			TupleBufferResetNotify(WorkerTupleBuffer, MyCQId, MyWorkerId);

			if (xact_commit)
				StartTransactionCommand();

			set_snapshot(estate, cqowner);
			CurrentResourceOwner = cqowner;
			MemoryContextSwitchTo(estate->es_query_cxt);

			estate->es_processed = 0;
			estate->es_filtered = 0;

			/*
			 * Run plan on a microbatch
			 */
			ExecutePlan(estate, queryDesc->planstate, operation,
					true, 0, timeoutms, ForwardScanDirection, dest);

			IncrementCQExecutions(1);
			TupleBufferClearPinnedSlots();

			if (state->long_xact)
			{
				if (TimestampDifferenceExceeds(last_commit, GetCurrentTimestamp(), LONG_RUNNING_XACT_DURATION))
					xact_commit = true;
				else
					xact_commit = false;
			}

			unset_snapshot(estate, cqowner);
			if (xact_commit)
			{
				CommitTransactionCommand();
				last_commit = GetCurrentTimestamp();
			}

			MemoryContextResetAndDeleteChildren(CQExecutionContext);
			MemoryContextSwitchTo(runcontext);
			CurrentResourceOwner = cqowner;

			if (estate->es_processed || estate->es_filtered)
			{
				/*
				 * If the CV query is such that the select does not return any tuples
				 * ex: select id where id=99; and id=99 does not exist, then this reset
				 * will fail. What will happen is that the worker will block at the latch for every
				 * allocated slot, TILL a cv returns a non-zero tuple, at which point
				 * the worker will resume a simple sleep for the threshold time.
				 */
				last_process = GetCurrentTimestamp();

				/*
				 * Send stats to the collector
				 */
				cq_stat_report(false);
			}

			/* Has the CQ been deactivated? */
			if (!entry->active)
			{
				if (ActiveSnapshotSet())
					unset_snapshot(estate, cqowner);
				if (IsTransactionState())
					CommitTransactionCommand();
				break;
			}
		}

		CurrentResourceOwner = cqowner;

		/*
		 * The cleanup functions below expect these things to be registered
		 */
		RegisterSnapshotOnOwner(estate->es_snapshot, cqowner);
		RegisterSnapshotOnOwner(queryDesc->snapshot, cqowner);
		RegisterSnapshotOnOwner(queryDesc->crosscheck_snapshot, cqowner);

		/* cleanup */
		ExecutorFinish(queryDesc);
		ExecutorEnd(queryDesc);
		FreeQueryDesc(queryDesc);
	}
	PG_CATCH();
	{
		EmitErrorReport();
		FlushErrorState();

		/* Since the worker is read-only, we can simply commit the transaction. */
		if (ActiveSnapshotSet())
			unset_snapshot(estate, cqowner);
		if (IsTransactionState())
			CommitTransactionCommand();

		TupleBufferUnpinAllPinnedSlots();
		TupleBufferClearReaders();

		/* This resets the es_query_ctx and in turn the CQExecutionContext */
		MemoryContextResetAndDeleteChildren(runcontext);

		IncrementCQErrors(1);

		if (continuous_query_crash_recovery)
			goto retry;
	}
	PG_END_TRY();

	(*dest->rShutdown) (dest);

	MemoryContextSwitchTo(oldcontext);
	MemoryContextDelete(runcontext);

	XactReadOnly = savereadonly;

	/*
	 * Remove proc-level stats
	 */
	cq_stat_report(true);
	cq_stat_send_purge(state->viewid, MyProcPid, CQ_STAT_WORKER);

	CurrentResourceOwner = owner;
}
Beispiel #23
0
Datei: fts.c Projekt: LJoNe/gpdb
/*
 * FtsProbeMain
 */
NON_EXEC_STATIC void
ftsMain(int argc, char *argv[])
{
	sigjmp_buf	local_sigjmp_buf;
	char	   *fullpath;

	IsUnderPostmaster = true;
	am_ftsprobe = true;

	/* Stay away from PMChildSlot */
	MyPMChildSlot = -1;

	/* reset MyProcPid */
	MyProcPid = getpid();
	
	/* Lose the postmaster's on-exit routines */
	on_exit_reset();

	/* Identify myself via ps */
	init_ps_display("ftsprobe process", "", "", "");

	SetProcessingMode(InitProcessing);

	/*
	 * reread postgresql.conf if requested
	 */
	pqsignal(SIGHUP, sigHupHandler);

	/*
	 * Presently, SIGINT will lead to autovacuum shutdown, because that's how
	 * we handle ereport(ERROR).  It could be improved however.
	 */
	pqsignal(SIGINT, ReqFtsFullScan);		/* request full-scan */
	pqsignal(SIGTERM, die);
	pqsignal(SIGQUIT, quickdie); /* we don't do any ftsprobe specific cleanup, just use the standard. */
	pqsignal(SIGALRM, handle_sig_alarm);

	pqsignal(SIGPIPE, SIG_IGN);
	pqsignal(SIGUSR1, procsignal_sigusr1_handler);
	/* We don't listen for async notifies */
	pqsignal(SIGUSR2, RequestShutdown);
	pqsignal(SIGFPE, FloatExceptionHandler);
	pqsignal(SIGCHLD, SIG_DFL);

	/*
	 * Copied from bgwriter
	 */
	CurrentResourceOwner = ResourceOwnerCreate(NULL, "FTS Probe");

	/* Early initialization */
	BaseInit();

	/* See InitPostgres()... */
	InitProcess();	
	InitBufferPoolBackend();
	InitXLOGAccess();

	SetProcessingMode(NormalProcessing);

	/*
	 * 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();

		/*
		 * 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);

	/*
	 * Add my PGPROC struct to the ProcArray.
	 *
	 * Once I have done this, I am visible to other backends!
	 */
	InitProcessPhase2();

	/*
	 * Initialize my entry in the shared-invalidation manager's array of
	 * per-backend data.
	 *
	 * Sets up MyBackendId, a unique backend identifier.
	 */
	MyBackendId = InvalidBackendId;

	SharedInvalBackendInit(false);

	if (MyBackendId > MaxBackends || MyBackendId <= 0)
		elog(FATAL, "bad backend id: %d", MyBackendId);

	/*
	 * bufmgr needs another initialization call too
	 */
	InitBufferPoolBackend();

	/* heap access requires the rel-cache */
	RelationCacheInitialize();
	InitCatalogCache();

	/*
	 * It's now possible to do real access to the system catalogs.
	 *
	 * Load relcache entries for the system catalogs.  This must create at
	 * least the minimum set of "nailed-in" cache entries.
	 */
	RelationCacheInitializePhase2();

	/*
	 * In order to access the catalog, we need a database, and a
	 * tablespace; our access to the heap is going to be slightly
	 * limited, so we'll just use some defaults.
	 */
	if (!FindMyDatabase(probeDatabase, &MyDatabaseId, &MyDatabaseTableSpace))
		ereport(FATAL,
				(errcode(ERRCODE_UNDEFINED_DATABASE),
				 errmsg("database \"%s\" does not exit", probeDatabase)));

	/* Now we can mark our PGPROC entry with the database ID */
	/* (We assume this is an atomic store so no lock is needed) */
	MyProc->databaseId = MyDatabaseId;

	fullpath = GetDatabasePath(MyDatabaseId, MyDatabaseTableSpace);

	SetDatabasePath(fullpath);

	RelationCacheInitializePhase3();

	/* shmem: publish probe pid */
	ftsProbeInfo->fts_probePid = MyProcPid;

	/* main loop */
	FtsLoop();

	/* One iteration done, go away */
	proc_exit(0);
}