143 lines
3.0 KiB
Go
143 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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// Limiatation
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// + Multi source replication is not supported
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// + Slave can not handle write transactions, so maybe readonly or strict_mode = 1 is better
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type MariadbGTIDHandler struct {
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Handler
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}
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func (h *MariadbGTIDHandler) 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 *MariadbGTIDHandler) FindBestSlaves(slaves []*Server) ([]*Server, error) {
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bestSlaves := []*Server{}
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ps := make([]uint64, len(slaves))
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lastIndex := -1
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var seq uint64
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for i, slave := range slaves {
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rr, err := slave.Execute("SELECT @@gtid_current_pos")
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if err != nil {
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return nil, errors.Trace(err)
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}
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str, _ := rr.GetString(0, 0)
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if len(str) == 0 {
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seq = 0
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} else {
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g, err := ParseMariadbGTIDSet(str)
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if err != nil {
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return nil, errors.Trace(err)
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}
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seq = g.(MariadbGTID).SequenceNumber
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}
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ps[i] = seq
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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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if ps[lastIndex] < seq {
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lastIndex = i
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bestSlaves = []*Server{slave}
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} else if ps[lastIndex] == seq {
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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 changeMasterToWithCurrentPos = `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_USE_GTID = current_pos`
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func (h *MariadbGTIDHandler) 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(changeMasterToWithCurrentPos,
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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 *MariadbGTIDHandler) 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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fname, _ := r.GetStringByName(0, "Master_Log_File")
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pos, _ := r.GetIntByName(0, "Read_Master_Log_Pos")
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return s.MasterPosWait(Position{fname, uint32(pos)}, 0)
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}
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func (h *MariadbGTIDHandler) WaitCatchMaster(s *Server, m *Server) error {
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r, err := m.Execute("SELECT @@gtid_binlog_pos")
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if err != nil {
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return errors.Trace(err)
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}
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pos, _ := r.GetString(0, 0)
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return h.waitUntilAfterGTID(s, pos)
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}
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func (h *MariadbGTIDHandler) CheckGTIDMode(slaves []*Server) error {
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return nil
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}
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func (h *MariadbGTIDHandler) waitUntilAfterGTID(s *Server, pos string) error {
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_, err := s.Execute(fmt.Sprintf("SELECT MASTER_GTID_WAIT('%s')", pos))
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return err
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}
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