// Return a replication state that will reparent a slave to the
// correct master for a specified position.
func (mysqld *Mysqld) ReparentPosition(slavePosition proto.ReplicationPosition) (rs *proto.ReplicationStatus, waitPosition proto.ReplicationPosition, reparentTime int64, err error) {
qr, err := mysqld.fetchSuperQuery(fmt.Sprintf("SELECT time_created_ns, new_addr, new_position, wait_position FROM _vt.reparent_log WHERE last_position = '%v'", slavePosition))
if err != nil {
return
}
if len(qr.Rows) != 1 {
err = fmt.Errorf("no reparent for position: %v", slavePosition)
return
}
reparentTime, err = qr.Rows[0][0].ParseInt64()
if err != nil {
err = fmt.Errorf("bad reparent time: %v %v %v", slavePosition, qr.Rows[0][0], err)
return
}
rs, err = proto.NewReplicationStatus(qr.Rows[0][1].String())
if err != nil {
return
}
rs.Position, err = mysqld.flavor.ParseReplicationPosition(qr.Rows[0][2].String())
if err != nil {
return
}
waitPosition, err = mysqld.flavor.ParseReplicationPosition(qr.Rows[0][3].String())
if err != nil {
return
}
return
}
func newSnapshotManifest(addr, mysqlAddr, masterAddr, dbName string, files []SnapshotFile, pos, masterPos proto.ReplicationPosition) (*SnapshotManifest, error) {
nrs, err := proto.NewReplicationStatus(masterAddr)
if err != nil {
return nil, err
}
rs := &SnapshotManifest{
Addr: addr,
DbName: dbName,
Files: files,
ReplicationStatus: nrs,
MasterPosition: masterPos,
}
sort.Sort(rs.Files)
rs.ReplicationStatus.Position = pos
return rs, nil
}
// setReadWrite: set the new master in read-write mode.
//
// replicationState: info slaves need to reparent themselves
// waitPosition: slaves can wait for this position when restarting replication
// timePromoted: this timestamp (unix nanoseconds) is inserted into _vt.replication_log to verify the replication config
func (mysqld *Mysqld) PromoteSlave(setReadWrite bool, hookExtraEnv map[string]string) (replicationStatus *proto.ReplicationStatus, waitPosition proto.ReplicationPosition, timePromoted int64, err error) {
if err = mysqld.StopSlave(hookExtraEnv); err != nil {
return
}
// If we are forced, we have to get our status as a master, not a slave.
var lastRepPos proto.ReplicationPosition
slaveStatus, err := mysqld.SlaveStatus()
if err == ErrNotSlave {
lastRepPos, err = mysqld.MasterPosition()
} else {
if err != nil {
return
}
lastRepPos = slaveStatus.Position
}
// Promote to master.
cmds := mysqld.flavor.PromoteSlaveCommands()
if err = mysqld.ExecuteSuperQueryList(cmds); err != nil {
return
}
// Write a row so there's something in the binlog before we fetch the
// master position. Otherwise, the slave may request a GTID that has
// already been purged from the binlog.
cmds = []string{
fmt.Sprintf("INSERT INTO _vt.replication_log (time_created_ns, note) VALUES (%v, 'first binlog event')", time.Now().UnixNano()),
}
if err = mysqld.ExecuteSuperQueryList(cmds); err != nil {
return
}
replicationPosition, err := mysqld.MasterPosition()
if err != nil {
return
}
mysqldAddr := mysqld.IpAddr()
replicationStatus, err = proto.NewReplicationStatus(mysqldAddr)
if err != nil {
return
}
replicationStatus.Position = replicationPosition
timePromoted = time.Now().UnixNano()
// write a row to verify that replication is functioning
cmds = []string{
fmt.Sprintf("INSERT INTO _vt.replication_log (time_created_ns, note) VALUES (%v, 'reparent check')", timePromoted),
}
if err = mysqld.ExecuteSuperQueryList(cmds); err != nil {
return
}
// this is the wait-point for checking replication
waitPosition, err = mysqld.MasterPosition()
if err != nil {
return
}
if waitPosition.Equal(replicationPosition) {
// We inserted a row, but our binlog position didn't change. This is a
// serious problem. We don't want to ever promote a master like that.
err = fmt.Errorf("cannot promote slave to master, non-functional binlogs")
return
}
cmds = []string{
fmt.Sprintf("INSERT INTO _vt.reparent_log (time_created_ns, last_position, new_addr, new_position, wait_position) VALUES (%v, '%v', '%v', '%v', '%v')",
timePromoted, lastRepPos, replicationStatus.MasterAddr(), replicationPosition, waitPosition),
}
if err = mysqld.ExecuteSuperQueryList(cmds); err != nil {
return
}
if setReadWrite {
err = mysqld.SetReadOnly(false)
}
return
}