Esempio n. 1
0
/*
 * Returns the replication apply delay in ms
 */
int
GetReplicationApplyDelay(void)
{
	/* use volatile pointer to prevent code rearrangement */
	volatile WalRcvData *walrcv = WalRcv;

	XLogRecPtr	receivePtr;
	XLogRecPtr	replayPtr;

	long		secs;
	int			usecs;

	SpinLockAcquire(&walrcv->mutex);
	receivePtr = walrcv->receivedUpto;
	SpinLockRelease(&walrcv->mutex);

	replayPtr = GetXLogReplayRecPtr(NULL);

	if (XLByteLE(receivePtr, replayPtr))
		return 0;

	TimestampDifference(GetCurrentChunkReplayStartTime(),
						GetCurrentTimestamp(),
						&secs, &usecs);

	return (((int) secs * 1000) + (usecs / 1000));
}
Esempio n. 2
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/*
 * Returns the replication apply delay in ms or -1
 * if the apply delay info is not available
 */
int
GetReplicationApplyDelay(void)
{
	WalRcvData *walrcv = WalRcv;
	XLogRecPtr	receivePtr;
	XLogRecPtr	replayPtr;

	long		secs;
	int			usecs;

	TimestampTz chunkReplayStartTime;

	SpinLockAcquire(&walrcv->mutex);
	receivePtr = walrcv->receivedUpto;
	SpinLockRelease(&walrcv->mutex);

	replayPtr = GetXLogReplayRecPtr(NULL);

	if (receivePtr == replayPtr)
		return 0;

	chunkReplayStartTime = GetCurrentChunkReplayStartTime();

	if (chunkReplayStartTime == 0)
		return -1;

	TimestampDifference(chunkReplayStartTime,
						GetCurrentTimestamp(),
						&secs, &usecs);

	return (((int) secs * 1000) + (usecs / 1000));
}
Esempio n. 3
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/*
 * pgespresso_stop_backup: finish taking an on-line backup dump
 *
 * Only parameter is the labelfile returned from pg_start_concurrent_backup
 *
 * Return is the XLOG filename containing end of backup location, combining
 * both the TLI and the end location. NOTE: the user is responsible for
 * ensuring that the last file is correctly archived.
 */
Datum
pgespresso_stop_backup(PG_FUNCTION_ARGS)
{
	XLogRecPtr	stoppoint;
	text	   *labelfile = PG_GETARG_TEXT_P(0);
	char	   *backupidstr;
	char		xlogfilename[MAXFNAMELEN];

	backupidstr = text_to_cstring(labelfile);

	if (!superuser() && !has_rolreplication(GetUserId()))
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
		 (errmsg("must be superuser or replication role to run a backup"))));

	#if PG_VERSION_NUM >= 90300
	{
		XLogSegNo	xlogsegno;
		TimeLineID	endtli;

		stoppoint = do_pg_stop_backup(backupidstr,
									  false,  /* don't wait for archive */
									  &endtli);

		XLByteToPrevSeg(stoppoint, xlogsegno);
		XLogFileName(xlogfilename, endtli, xlogsegno);
	}
	#else
	{
		uint32		xlogid;
		uint32		xlogseg;

		stoppoint = do_pg_stop_backup(backupidstr,
									  false);  /* don't wait for archive */

		/*
		 * In 9.2 the do_pg_stop_backup doesn't return the timeline ID and
		 * ThisTimeLineID is always 0 in a normal backend during recovery.
		 * We get latest redo apply position timeline and we update it globally
		 */
		if (RecoveryInProgress()) {
			TimeLineID	replayTLI;

			GetXLogReplayRecPtr(&replayTLI);
			ThisTimeLineID = replayTLI;
			elog(DEBUG1, "updated ThisTimeLineID = %u", ThisTimeLineID);
		}

		XLByteToPrevSeg(stoppoint, xlogid, xlogseg);
		XLogFileName(xlogfilename, ThisTimeLineID, xlogid, xlogseg);
	}
	#endif

	PG_RETURN_TEXT_P(cstring_to_text(xlogfilename));
}
Esempio n. 4
0
/*
 * Report the last WAL replay location (same format as pg_start_backup etc)
 *
 * This is useful for determining how much of WAL is visible to read-only
 * connections during recovery.
 */
Datum
pg_last_xlog_replay_location(PG_FUNCTION_ARGS)
{
	XLogRecPtr	recptr;

	recptr = GetXLogReplayRecPtr(NULL);

	if (recptr == 0)
		PG_RETURN_NULL();

	PG_RETURN_LSN(recptr);
}
Esempio n. 5
0
/*
 * Report the last WAL replay location (same format as pg_start_backup etc)
 *
 * This is useful for determining how much of WAL is visible to read-only
 * connections during recovery.
 */
Datum
pg_last_xlog_replay_location(PG_FUNCTION_ARGS)
{
	XLogRecPtr	recptr;
	char		location[MAXFNAMELEN];

	recptr = GetXLogReplayRecPtr(NULL);

	if (recptr.xlogid == 0 && recptr.xrecoff == 0)
		PG_RETURN_NULL();

	snprintf(location, sizeof(location), "%X/%X",
			 recptr.xlogid, recptr.xrecoff);
	PG_RETURN_TEXT_P(cstring_to_text(location));
}
Esempio n. 6
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/*
 * read_page callback for logical decoding contexts.
 *
 * Public because it would likely be very helpful for someone writing another
 * output method outside walsender, e.g. in a bgworker.
 *
 * TODO: The walsender has it's own version of this, but it relies on the
 * walsender's latch being set whenever WAL is flushed. No such infrastructure
 * exists for normal backends, so we have to do a check/sleep/repeat style of
 * loop for now.
 */
int
logical_read_local_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr,
	int reqLen, XLogRecPtr targetRecPtr, char *cur_page, TimeLineID *pageTLI)
{
	XLogRecPtr	flushptr,
				loc;
	int			count;

	loc = targetPagePtr + reqLen;
	while (1)
	{
		/*
		 * TODO: we're going to have to do something more intelligent about
		 * timelines on standbys. Use readTimeLineHistory() and
		 * tliOfPointInHistory() to get the proper LSN? For now we'll catch
		 * that case earlier, but the code and TODO is left in here for when
		 * that changes.
		 */
		if (!RecoveryInProgress())
		{
			*pageTLI = ThisTimeLineID;
			flushptr = GetFlushRecPtr();
		}
		else
			flushptr = GetXLogReplayRecPtr(pageTLI);

		if (loc <= flushptr)
			break;

		CHECK_FOR_INTERRUPTS();
		pg_usleep(1000L);
	}

	/* more than one block available */
	if (targetPagePtr + XLOG_BLCKSZ <= flushptr)
		count = XLOG_BLCKSZ;
	/* not enough data there */
	else if (targetPagePtr + reqLen > flushptr)
		return -1;
	/* part of the page available */
	else
		count = flushptr - targetPagePtr;

	XLogRead(cur_page, *pageTLI, targetPagePtr, XLOG_BLCKSZ);

	return count;
}
Esempio n. 7
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/*
 * Send reply message to primary, indicating our current XLOG positions and
 * the current time.
 */
static void
XLogWalRcvSendReply(void)
{
	char		buf[sizeof(StandbyReplyMessage) + 1];
	TimestampTz	now;

	/*
	 * If the user doesn't want status to be reported to the master, be sure
	 * to exit before doing anything at all.
	 */
	if (wal_receiver_status_interval <= 0)
		return;

	/* Get current timestamp. */
	now = GetCurrentTimestamp();

	/*
	 * We can compare the write and flush positions to the last message we
	 * sent without taking any lock, but the apply position requires a spin
	 * lock, so we don't check that unless something else has changed or 10
	 * seconds have passed.  This means that the apply log position will
	 * appear, from the master's point of view, to lag slightly, but since
	 * this is only for reporting purposes and only on idle systems, that's
	 * probably OK.
	 */
	if (XLByteEQ(reply_message.write, LogstreamResult.Write)
		&& XLByteEQ(reply_message.flush, LogstreamResult.Flush)
		&& !TimestampDifferenceExceeds(reply_message.sendTime, now,
			wal_receiver_status_interval * 1000))
		return;

	/* Construct a new message. */
	reply_message.write = LogstreamResult.Write;
	reply_message.flush = LogstreamResult.Flush;
	reply_message.apply = GetXLogReplayRecPtr();
	reply_message.sendTime = now;

	elog(DEBUG2, "sending write %X/%X flush %X/%X apply %X/%X",
				 reply_message.write.xlogid, reply_message.write.xrecoff,
				 reply_message.flush.xlogid, reply_message.flush.xrecoff,
				 reply_message.apply.xlogid, reply_message.apply.xrecoff);

	/* Prepend with the message type and send it. */
	buf[0] = 'r';
	memcpy(&buf[1], &reply_message, sizeof(StandbyReplyMessage));
	walrcv_send(buf, sizeof(StandbyReplyMessage) + 1);
}
Esempio n. 8
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/*
 * pgespresso_start_backup: set up for taking an on-line backup dump
 *
 * Essentially what this does is to return a backup label file that the
 * user is responsible for placing in the $PGDATA of the backup AFTER
 * the backup has been taken.  The label file must not be written to the
 * data directory of the server from which the backup is taken because
 * this type of backup presumes and allows that more than one backup
 * may be in progress at any one time.  The label file
 * contains the user-supplied label string (typically this would be used
 * to tell where the backup dump will be stored) and the starting time and
 * starting WAL location for the dump.
 */
Datum
pgespresso_start_backup(PG_FUNCTION_ARGS)
{
	text	   *backupid = PG_GETARG_TEXT_P(0);
	bool		fast = PG_GETARG_BOOL(1);
	char	   *backupidstr;
	char       *labelfile;

	backupidstr = text_to_cstring(backupid);

	if (!superuser() && !has_rolreplication(GetUserId()))
		ereport(ERROR,
				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
		   errmsg("must be superuser or replication role to run a backup")));

	/*
	 * ThisTimeLineID is always 0 in a normal backend during recovery.
	 * We get latest redo apply position timeline and we update it globally
	 * to make do_pg_start_backup use the correct value when generating
	 * the backup label text
	 */
	if (RecoveryInProgress()) {
		TimeLineID	replayTLI;

		GetXLogReplayRecPtr(&replayTLI);
		ThisTimeLineID = replayTLI;
		elog(DEBUG1, "updated ThisTimeLineID = %u", ThisTimeLineID);
	}

	/*
	 * Starting from 9.3 the do_pg_start_backup returns the timeline ID
	 * in *starttli_p additional argument
	 */
	#if PG_VERSION_NUM >= 90300
		do_pg_start_backup(backupidstr, fast, NULL, &labelfile);
	#else
		do_pg_start_backup(backupidstr, fast, &labelfile);
	#endif

	PG_RETURN_TEXT_P(cstring_to_text(labelfile));
}
Esempio n. 9
0
/*
 * IsCheckpointOnSchedule -- are we on schedule to finish this checkpoint
 *		 (or restartpoint) in time?
 *
 * Compares the current progress against the time/segments elapsed since last
 * checkpoint, and returns true if the progress we've made this far is greater
 * than the elapsed time/segments.
 */
static bool
IsCheckpointOnSchedule(double progress)
{
	XLogRecPtr	recptr;
	struct timeval now;
	double		elapsed_xlogs,
				elapsed_time;

	Assert(ckpt_active);

	/* Scale progress according to checkpoint_completion_target. */
	progress *= CheckPointCompletionTarget;

	/*
	 * Check against the cached value first. Only do the more expensive
	 * calculations once we reach the target previously calculated. Since
	 * neither time or WAL insert pointer moves backwards, a freshly
	 * calculated value can only be greater than or equal to the cached value.
	 */
	if (progress < ckpt_cached_elapsed)
		return false;

	/*
	 * Check progress against WAL segments written and CheckPointSegments.
	 *
	 * We compare the current WAL insert location against the location
	 * computed before calling CreateCheckPoint. The code in XLogInsert that
	 * actually triggers a checkpoint when CheckPointSegments is exceeded
	 * compares against RedoRecptr, so this is not completely accurate.
	 * However, it's good enough for our purposes, we're only calculating an
	 * estimate anyway.
	 *
	 * During recovery, we compare last replayed WAL record's location with
	 * the location computed before calling CreateRestartPoint. That maintains
	 * the same pacing as we have during checkpoints in normal operation, but
	 * we might exceed max_wal_size by a fair amount. That's because there can
	 * be a large gap between a checkpoint's redo-pointer and the checkpoint
	 * record itself, and we only start the restartpoint after we've seen the
	 * checkpoint record. (The gap is typically up to CheckPointSegments *
	 * checkpoint_completion_target where checkpoint_completion_target is the
	 * value that was in effect when the WAL was generated).
	 */
	if (RecoveryInProgress())
		recptr = GetXLogReplayRecPtr(NULL);
	else
		recptr = GetInsertRecPtr();
	elapsed_xlogs = (((double) (recptr - ckpt_start_recptr)) / XLogSegSize) / CheckPointSegments;

	if (progress < elapsed_xlogs)
	{
		ckpt_cached_elapsed = elapsed_xlogs;
		return false;
	}

	/*
	 * Check progress against time elapsed and checkpoint_timeout.
	 */
	gettimeofday(&now, NULL);
	elapsed_time = ((double) ((pg_time_t) now.tv_sec - ckpt_start_time) +
					now.tv_usec / 1000000.0) / CheckPointTimeout;

	if (progress < elapsed_time)
	{
		ckpt_cached_elapsed = elapsed_time;
		return false;
	}

	/* It looks like we're on schedule. */
	return true;
}
Esempio n. 10
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);
	}
}
Esempio n. 11
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;
}
Esempio n. 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;
}