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vreplication: bug: make row streaming more robust #5114

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Merged
sougou merged 1 commit into from
Aug 21, 2019
Merged

vreplication: bug: make row streaming more robust #5114

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59 changes: 29 additions & 30 deletions go/vt/vttablet/tabletserver/vstreamer/rowstreamer.go
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Original file line number Diff line number Diff line change
Expand Up @@ -19,11 +19,11 @@ package vstreamer
import (
"context"
"fmt"
"sync"

"vitess.io/vitess/go/mysql"
"vitess.io/vitess/go/sqltypes"
"vitess.io/vitess/go/vt/dbconfigs"
"vitess.io/vitess/go/vt/log"
"vitess.io/vitess/go/vt/sqlparser"
"vitess.io/vitess/go/vt/vtgate/vindexes"
"vitess.io/vitess/go/vt/vttablet/tabletserver/schema"
Expand Down Expand Up @@ -172,15 +172,10 @@ func (rs *rowStreamer) buildSelect() (string, error) {
}

func (rs *rowStreamer) streamQuery(conn *mysql.Conn, send func(*binlogdatapb.VStreamRowsResponse) error) error {
unlock, gtid, err := rs.lockTable()
gtid, err := rs.startStreaming(conn)
if err != nil {
return err
}
defer unlock()

if err := conn.ExecuteStreamFetch(rs.sendQuery); err != nil {
return err
}

// first call the callback with the fields
flds, err := conn.Fields()
Expand All @@ -203,9 +198,6 @@ func (rs *rowStreamer) streamQuery(conn *mysql.Conn, send func(*binlogdatapb.VSt
if err != nil {
return fmt.Errorf("stream send error: %v", err)
}
if err := unlock(); err != nil {
return err
}

response := &binlogdatapb.VStreamRowsResponse{}
lastpk := make([]sqltypes.Value, len(rs.pkColumns))
Expand Down Expand Up @@ -262,33 +254,40 @@ func (rs *rowStreamer) streamQuery(conn *mysql.Conn, send func(*binlogdatapb.VSt
return nil
}

func (rs *rowStreamer) lockTable() (unlock func() error, gtid string, err error) {
conn, err := rs.mysqlConnect()
func (rs *rowStreamer) startStreaming(conn *mysql.Conn) (string, error) {
lockConn, err := rs.mysqlConnect()
if err != nil {
return nil, "", err
return "", err
}
// To be safe, always unlock tables, even if lock tables might fail.
defer func() {
_, err := lockConn.ExecuteFetch("unlock tables", 0, false)
if err != nil {
log.Warning("Unlock tables failed: %v", err)
} else {
log.Infof("Tables unlocked", rs.plan.Table.Name)
}
lockConn.Close()
}()

log.Infof("Locking table %s for copying", rs.plan.Table.Name)
// mysql recommends this before locking tables.
if _, err := conn.ExecuteFetch("set autocommit=0", 0, false); err != nil {
return nil, "", err
if _, err := lockConn.ExecuteFetch("set autocommit=0", 0, false); err != nil {
return "", err
}
if _, err := conn.ExecuteFetch(fmt.Sprintf("lock tables %s read", sqlparser.String(sqlparser.NewTableIdent(rs.plan.Table.Name))), 0, false); err != nil {
return nil, "", err
}
var once sync.Once
unlock = func() error {
var err error
once.Do(func() {
_, err = conn.ExecuteFetch("unlock tables", 0, false)
conn.Close()
})
return err
if _, err := lockConn.ExecuteFetch(fmt.Sprintf("lock tables %s read", sqlparser.String(sqlparser.NewTableIdent(rs.plan.Table.Name))), 0, false); err != nil {
return "", err
}
pos, err := conn.MasterPosition()
pos, err := lockConn.MasterPosition()
if err != nil {
unlock()
return nil, "", err
return "", err
}
return unlock, mysql.EncodePosition(pos), nil

if err := conn.ExecuteStreamFetch(rs.sendQuery); err != nil {
return "", err
}

return mysql.EncodePosition(pos), nil
}

func (rs *rowStreamer) mysqlConnect() (*mysql.Conn, error) {
Expand Down