gh-ost/vendor/github.com/siddontang/go-mysql/failover/mariadb_gtid_handler.go

143 lines
3.0 KiB
Go

package failover
import (
"fmt"
"net"
"github.com/juju/errors"
. "github.com/siddontang/go-mysql/mysql"
)
// Limiatation
// + Multi source replication is not supported
// + Slave can not handle write transactions, so maybe readonly or strict_mode = 1 is better
type MariadbGTIDHandler struct {
Handler
}
func (h *MariadbGTIDHandler) Promote(s *Server) error {
if err := h.WaitRelayLogDone(s); err != nil {
return errors.Trace(err)
}
if err := s.StopSlave(); err != nil {
return errors.Trace(err)
}
return nil
}
func (h *MariadbGTIDHandler) FindBestSlaves(slaves []*Server) ([]*Server, error) {
bestSlaves := []*Server{}
ps := make([]uint64, len(slaves))
lastIndex := -1
var seq uint64
for i, slave := range slaves {
rr, err := slave.Execute("SELECT @@gtid_current_pos")
if err != nil {
return nil, errors.Trace(err)
}
str, _ := rr.GetString(0, 0)
if len(str) == 0 {
seq = 0
} else {
g, err := ParseMariadbGTID(str)
if err != nil {
return nil, errors.Trace(err)
}
seq = g.SequenceNumber
}
ps[i] = seq
if lastIndex == -1 {
lastIndex = i
bestSlaves = []*Server{slave}
} else {
if ps[lastIndex] < seq {
lastIndex = i
bestSlaves = []*Server{slave}
} else if ps[lastIndex] == seq {
// these two slaves have same data,
bestSlaves = append(bestSlaves, slave)
}
}
}
return bestSlaves, nil
}
const changeMasterToWithCurrentPos = `CHANGE MASTER TO
MASTER_HOST = "%s", MASTER_PORT = %s,
MASTER_USER = "%s", MASTER_PASSWORD = "%s",
MASTER_USE_GTID = current_pos`
func (h *MariadbGTIDHandler) ChangeMasterTo(s *Server, m *Server) error {
if err := h.WaitRelayLogDone(s); err != nil {
return errors.Trace(err)
}
if err := s.StopSlave(); err != nil {
return errors.Trace(err)
}
if err := s.ResetSlave(); err != nil {
return errors.Trace(err)
}
host, port, _ := net.SplitHostPort(m.Addr)
if _, err := s.Execute(fmt.Sprintf(changeMasterToWithCurrentPos,
host, port, m.ReplUser.Name, m.ReplUser.Password)); err != nil {
return errors.Trace(err)
}
if err := s.StartSlave(); err != nil {
return errors.Trace(err)
}
return nil
}
func (h *MariadbGTIDHandler) WaitRelayLogDone(s *Server) error {
if err := s.StopSlaveIOThread(); err != nil {
return errors.Trace(err)
}
r, err := s.SlaveStatus()
if err != nil {
return errors.Trace(err)
}
fname, _ := r.GetStringByName(0, "Master_Log_File")
pos, _ := r.GetIntByName(0, "Read_Master_Log_Pos")
return s.MasterPosWait(Position{Name: fname, Pos: uint32(pos)}, 0)
}
func (h *MariadbGTIDHandler) WaitCatchMaster(s *Server, m *Server) error {
r, err := m.Execute("SELECT @@gtid_binlog_pos")
if err != nil {
return errors.Trace(err)
}
pos, _ := r.GetString(0, 0)
return h.waitUntilAfterGTID(s, pos)
}
func (h *MariadbGTIDHandler) CheckGTIDMode(slaves []*Server) error {
return nil
}
func (h *MariadbGTIDHandler) waitUntilAfterGTID(s *Server, pos string) error {
_, err := s.Execute(fmt.Sprintf("SELECT MASTER_GTID_WAIT('%s')", pos))
return err
}