// InitMaster breaks slaves replication, get the current MySQL replication
// position, insert a row in the reparent_journal table, and returns
// the replication position
func (agent *ActionAgent) InitMaster(ctx context.Context) (string, error) {
// we need to insert something in the binlogs, so we can get the
// current position. Let's just use the mysqlctl.CreateReparentJournal commands.
cmds := mysqlctl.CreateReparentJournal()
if err := agent.MysqlDaemon.ExecuteSuperQueryList(cmds); err != nil {
return "", err
}
// get the current replication position
pos, err := agent.MysqlDaemon.MasterPosition()
if err != nil {
return "", err
}
// Set the server read-write, from now on we can accept real
// client writes. Note that if semi-sync replication is enabled,
// we'll still need some slaves to be able to commit
// transactions.
if err := agent.MysqlDaemon.SetReadOnly(false); err != nil {
return "", err
}
// Change our type to master if not already
if _, err := agent.TopoServer.UpdateTabletFields(ctx, agent.TabletAlias, func(tablet *topodatapb.Tablet) error {
tablet.Type = topodatapb.TabletType_MASTER
tablet.HealthMap = nil
return nil
}); err != nil {
return "", err
}
agent.initReplication = true
return replication.EncodePosition(pos), nil
}
// PopulateReparentJournal adds an entry into the reparent_journal table.
func (agent *ActionAgent) PopulateReparentJournal(ctx context.Context, timeCreatedNS int64, actionName string, masterAlias *topodatapb.TabletAlias, position string) error {
pos, err := replication.DecodePosition(position)
if err != nil {
return err
}
cmds := mysqlctl.CreateReparentJournal()
cmds = append(cmds, mysqlctl.PopulateReparentJournal(timeCreatedNS, actionName, topoproto.TabletAliasString(masterAlias), pos))
return agent.MysqlDaemon.ExecuteSuperQueryList(cmds)
}
// InitMaster enables writes and returns the replication position.
func (agent *ActionAgent) InitMaster(ctx context.Context) (string, error) {
if err := agent.lock(ctx); err != nil {
return "", err
}
defer agent.unlock()
// Initializing as master implies undoing any previous "do not replicate".
agent.setSlaveStopped(false)
// we need to insert something in the binlogs, so we can get the
// current position. Let's just use the mysqlctl.CreateReparentJournal commands.
cmds := mysqlctl.CreateReparentJournal()
if err := agent.MysqlDaemon.ExecuteSuperQueryList(ctx, cmds); err != nil {
return "", err
}
// get the current replication position
pos, err := agent.MysqlDaemon.MasterPosition()
if err != nil {
return "", err
}
// If using semi-sync, we need to enable it before going read-write.
if *enableSemiSync {
if err := agent.enableSemiSync(true); err != nil {
return "", err
}
}
// Set the server read-write, from now on we can accept real
// client writes. Note that if semi-sync replication is enabled,
// we'll still need some slaves to be able to commit transactions.
if err := agent.MysqlDaemon.SetReadOnly(false); err != nil {
return "", err
}
// Change our type to master if not already
if _, err := agent.TopoServer.UpdateTabletFields(ctx, agent.TabletAlias, func(tablet *topodatapb.Tablet) error {
tablet.Type = topodatapb.TabletType_MASTER
return nil
}); err != nil {
return "", err
}
// and refresh our state
agent.initReplication = true
if err := agent.refreshTablet(ctx, "InitMaster"); err != nil {
return "", err
}
return replication.EncodePosition(pos), nil
}
// PopulateReparentJournal adds an entry into the reparent_journal table.
func (agent *ActionAgent) PopulateReparentJournal(ctx context.Context, timeCreatedNS int64, actionName string, masterAlias *pb.TabletAlias, pos myproto.ReplicationPosition) error {
cmds := mysqlctl.CreateReparentJournal()
cmds = append(cmds, mysqlctl.PopulateReparentJournal(timeCreatedNS, actionName, topoproto.TabletAliasString(masterAlias), pos))
return agent.MysqlDaemon.ExecuteSuperQueryList(cmds)
}