142 lines
3.0 KiB
Go
142 lines
3.0 KiB
Go
package failover
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import (
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"fmt"
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"net"
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"github.com/juju/errors"
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. "github.com/siddontang/go-mysql/mysql"
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)
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type MysqlGTIDHandler struct {
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Handler
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}
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func (h *MysqlGTIDHandler) Promote(s *Server) error {
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if err := h.WaitRelayLogDone(s); err != nil {
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return errors.Trace(err)
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}
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if err := s.StopSlave(); err != nil {
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return errors.Trace(err)
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}
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return nil
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}
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func (h *MysqlGTIDHandler) FindBestSlaves(slaves []*Server) ([]*Server, error) {
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// MHA use Relay_Master_Log_File and Exec_Master_Log_Pos to determind which is the best slave
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bestSlaves := []*Server{}
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ps := make([]Position, len(slaves))
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lastIndex := -1
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for i, slave := range slaves {
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pos, err := slave.FetchSlaveExecutePos()
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if err != nil {
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return nil, errors.Trace(err)
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}
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ps[i] = pos
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if lastIndex == -1 {
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lastIndex = i
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bestSlaves = []*Server{slave}
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} else {
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switch ps[lastIndex].Compare(pos) {
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case 1:
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//do nothing
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case -1:
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lastIndex = i
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bestSlaves = []*Server{slave}
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case 0:
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// these two slaves have same data,
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bestSlaves = append(bestSlaves, slave)
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}
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}
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}
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return bestSlaves, nil
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}
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const changeMasterToWithAuto = `CHANGE MASTER TO
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MASTER_HOST = "%s", MASTER_PORT = %s,
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MASTER_USER = "%s", MASTER_PASSWORD = "%s",
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MASTER_AUTO_POSITION = 1`
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func (h *MysqlGTIDHandler) ChangeMasterTo(s *Server, m *Server) error {
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if err := h.WaitRelayLogDone(s); err != nil {
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return errors.Trace(err)
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}
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if err := s.StopSlave(); err != nil {
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return errors.Trace(err)
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}
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if err := s.ResetSlave(); err != nil {
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return errors.Trace(err)
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}
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host, port, _ := net.SplitHostPort(m.Addr)
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if _, err := s.Execute(fmt.Sprintf(changeMasterToWithAuto,
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host, port, m.ReplUser.Name, m.ReplUser.Password)); err != nil {
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return errors.Trace(err)
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}
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if err := s.StartSlave(); err != nil {
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return errors.Trace(err)
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}
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return nil
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}
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func (h *MysqlGTIDHandler) WaitRelayLogDone(s *Server) error {
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if err := s.StopSlaveIOThread(); err != nil {
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return errors.Trace(err)
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}
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r, err := s.SlaveStatus()
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if err != nil {
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return errors.Trace(err)
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}
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retrieved, _ := r.GetStringByName(0, "Retrieved_Gtid_Set")
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// may only support MySQL version >= 5.6.9
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// see http://dev.mysql.com/doc/refman/5.6/en/gtid-functions.html
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return h.waitUntilAfterGTIDs(s, retrieved)
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}
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func (h *MysqlGTIDHandler) WaitCatchMaster(s *Server, m *Server) error {
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r, err := m.MasterStatus()
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if err != nil {
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return errors.Trace(err)
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}
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masterGTIDSet, _ := r.GetStringByName(0, "Executed_Gtid_Set")
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return h.waitUntilAfterGTIDs(s, masterGTIDSet)
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}
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func (h *MysqlGTIDHandler) CheckGTIDMode(slaves []*Server) error {
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for i := 0; i < len(slaves); i++ {
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mode, err := slaves[i].MysqlGTIDMode()
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if err != nil {
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return errors.Trace(err)
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} else if mode != GTIDModeOn {
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return errors.Errorf("%s use not GTID mode", slaves[i].Addr)
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}
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}
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return nil
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}
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func (h *MysqlGTIDHandler) waitUntilAfterGTIDs(s *Server, gtids string) error {
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_, err := s.Execute(fmt.Sprintf("SELECT WAIT_UNTIL_SQL_THREAD_AFTER_GTIDS('%s')", gtids))
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return err
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}
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