예제 #1
0
// Stream starts streaming binlog events using the settings from NewStreamer().
func (bls *Streamer) Stream(ctx context.Context) (err error) {
	stopPos := bls.startPos
	defer func() {
		if err != nil && err != mysqlctl.ErrBinlogUnavailable {
			err = fmt.Errorf("stream error @ %v: %v", stopPos, err)
		}
		log.Infof("stream ended @ %v, err = %v", stopPos, err)
	}()

	if bls.conn, err = bls.mysqld.NewSlaveConnection(); err != nil {
		return err
	}
	defer bls.conn.Close()

	// Check that the default charsets match, if the client specified one.
	// Note that Streamer uses the settings for the 'dba' user, while
	// BinlogPlayer uses the 'filtered' user, so those are the ones whose charset
	// must match. Filtered replication should still succeed even with a default
	// mismatch, since we pass per-statement charset info. However, Vitess in
	// general doesn't support servers with different default charsets, so we
	// treat it as a configuration error.
	if bls.clientCharset != nil {
		cs, err := sqldb.GetCharset(bls.conn)
		if err != nil {
			return fmt.Errorf("can't get charset to check binlog stream: %v", err)
		}
		log.Infof("binlog stream client charset = %v, server charset = %v", *bls.clientCharset, cs)
		if *cs != *bls.clientCharset {
			return fmt.Errorf("binlog stream client charset (%v) doesn't match server (%v)", bls.clientCharset, cs)
		}
	}

	var events <-chan replication.BinlogEvent
	if bls.timestamp != 0 {
		// MySQL 5.6 only: We are going to start reading the
		// logs from the beginning of a binlog file. That is
		// going to send us the PREVIOUS_GTIDS_EVENT that
		// contains the starting GTIDSet, and we will save
		// that as the current position.
		bls.usePreviousGTIDs = true
		events, err = bls.conn.StartBinlogDumpFromBinlogBeforeTimestamp(ctx, bls.timestamp)
	} else if !bls.startPos.IsZero() {
		// MySQL 5.6 only: we are starting from a random
		// binlog position. It turns out we will receive a
		// PREVIOUS_GTIDS_EVENT event, that has a GTIDSet
		// extracted from the binlogs. It is not related to
		// the starting position we pass in, it seems it is
		// just the PREVIOUS_GTIDS_EVENT from the file we're reading.
		// So we have to skip it.
		events, err = bls.conn.StartBinlogDumpFromPosition(ctx, bls.startPos)
	} else {
		bls.startPos, events, err = bls.conn.StartBinlogDumpFromCurrent(ctx)
	}
	if err != nil {
		return err
	}
	// parseEvents will loop until the events channel is closed, the
	// service enters the SHUTTING_DOWN state, or an error occurs.
	stopPos, err = bls.parseEvents(ctx, events)
	return err
}
예제 #2
0
// ApplyBinlogEvents makes an RPC request to BinlogServer
// and processes the events. It will return nil if the provided context
// was canceled, or if we reached the stopping point.
// It will return io.EOF if the server stops sending us updates.
// It may return any other error it encounters.
func (blp *BinlogPlayer) ApplyBinlogEvents(ctx context.Context) error {
	// Instantiate the throttler based on the configuration stored in the db.
	maxTPS, maxReplicationLag, err := blp.readThrottlerSettings()
	if err != nil {
		log.Error(err)
		return err
	}
	t, err := throttler.NewThrottler(
		fmt.Sprintf("BinlogPlayer/%d", blp.uid), "transactions", 1 /* threadCount */, maxTPS, maxReplicationLag)
	if err != nil {
		err := fmt.Errorf("failed to instantiate throttler: %v", err)
		log.Error(err)
		return err
	}
	defer t.Close()

	// Log the mode of operation and when the player stops.
	if len(blp.tables) > 0 {
		log.Infof("BinlogPlayer client %v for tables %v starting @ '%v', server: %v",
			blp.uid,
			blp.tables,
			blp.position,
			blp.tablet,
		)
	} else {
		log.Infof("BinlogPlayer client %v for keyrange '%v-%v' starting @ '%v', server: %v",
			blp.uid,
			hex.EncodeToString(blp.keyRange.Start),
			hex.EncodeToString(blp.keyRange.End),
			blp.position,
			blp.tablet,
		)
	}
	if !blp.stopPosition.IsZero() {
		// We need to stop at some point. Sanity check the point.
		switch {
		case blp.position.Equal(blp.stopPosition):
			log.Infof("Not starting BinlogPlayer, we're already at the desired position %v", blp.stopPosition)
			return nil
		case blp.position.AtLeast(blp.stopPosition):
			return fmt.Errorf("starting point %v greater than stopping point %v", blp.position, blp.stopPosition)
		default:
			log.Infof("Will stop player when reaching %v", blp.stopPosition)
		}
	}

	clientFactory, ok := clientFactories[*binlogPlayerProtocol]
	if !ok {
		return fmt.Errorf("no binlog player client factory named %v", *binlogPlayerProtocol)
	}
	blplClient := clientFactory()
	err = blplClient.Dial(blp.tablet, *BinlogPlayerConnTimeout)
	if err != nil {
		err := fmt.Errorf("error dialing binlog server: %v", err)
		log.Error(err)
		return err
	}
	defer blplClient.Close()

	// Get the current charset of our connection, so we can ask the stream server
	// to check that they match. The streamer will also only send per-statement
	// charset data if that statement's charset is different from what we specify.
	if dbClient, ok := blp.dbClient.(*DBClient); ok {
		blp.defaultCharset, err = sqldb.GetCharset(dbClient.dbConn)
		if err != nil {
			return fmt.Errorf("can't get charset to request binlog stream: %v", err)
		}
		log.Infof("original charset: %v", blp.defaultCharset)
		blp.currentCharset = blp.defaultCharset
		// Restore original charset when we're done.
		defer func() {
			// If the connection has been closed, there's no need to restore
			// this connection-specific setting.
			if dbClient.dbConn == nil {
				return
			}
			log.Infof("restoring original charset %v", blp.defaultCharset)
			if csErr := sqldb.SetCharset(dbClient.dbConn, blp.defaultCharset); csErr != nil {
				log.Errorf("can't restore original charset %v: %v", blp.defaultCharset, csErr)
			}
		}()
	}

	var stream BinlogTransactionStream
	if len(blp.tables) > 0 {
		stream, err = blplClient.StreamTables(ctx, replication.EncodePosition(blp.position), blp.tables, blp.defaultCharset)
	} else {
		stream, err = blplClient.StreamKeyRange(ctx, replication.EncodePosition(blp.position), blp.keyRange, blp.defaultCharset)
	}
	if err != nil {
		err := fmt.Errorf("error sending streaming query to binlog server: %v", err)
		log.Error(err)
		return err
	}

	for {
		// Block if we are throttled.
		for {
			backoff := t.Throttle(0 /* threadID */)
			if backoff == throttler.NotThrottled {
				break
			}
			// We don't bother checking for context cancellation here because the
			// sleep will block only up to 1 second. (Usually, backoff is 1s / rate
			// e.g. a rate of 1000 TPS results into a backoff of 1 ms.)
			time.Sleep(backoff)
		}

		// get the response
		response, err := stream.Recv()
		if err != nil {
			switch err {
			case context.Canceled:
				return nil
			default:
				// if the context is canceled, we
				// return nil (some RPC
				// implementations will remap the
				// context error to their own errors)
				select {
				case <-ctx.Done():
					if ctx.Err() == context.Canceled {
						return nil
					}
				default:
				}
				return fmt.Errorf("Error received from Stream %v", err)
			}
		}

		// process the transaction
		for {
			ok, err = blp.processTransaction(response)
			if err != nil {
				return fmt.Errorf("Error in processing binlog event %v", err)
			}
			if ok {
				if !blp.stopPosition.IsZero() {
					if blp.position.AtLeast(blp.stopPosition) {
						log.Infof("Reached stopping position, done playing logs")
						return nil
					}
				}
				break
			}
			log.Infof("Retrying txn")
			time.Sleep(1 * time.Second)
		}
	}
}