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Remove unnecessary usage of FLUSH TABLES WITH READ LOCK #4849

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merged 1 commit into from
May 7, 2019
Merged

Remove unnecessary usage of FLUSH TABLES WITH READ LOCK #4849

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7 changes: 2 additions & 5 deletions go/vt/mysqlctl/fakemysqldaemon/fakemysqldaemon.go
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Original file line number Diff line number Diff line change
Expand Up @@ -90,9 +90,6 @@ type FakeMysqlDaemon struct {
// (as "%v:%v"). If it doesn't match, SetMaster will return an error.
SetMasterInput string

// DemoteMasterPosition is returned by DemoteMaster
DemoteMasterPosition mysql.Position

// WaitMasterPosition is checked by WaitMasterPos, if the
// same it returns nil, if different it returns an error
WaitMasterPosition mysql.Position
Expand Down Expand Up @@ -307,9 +304,9 @@ func (fmd *FakeMysqlDaemon) WaitForReparentJournal(ctx context.Context, timeCrea
return nil
}

// DemoteMaster is part of the MysqlDaemon interface
// Deprecated: use mysqld.MasterPosition() instead
func (fmd *FakeMysqlDaemon) DemoteMaster() (mysql.Position, error) {
return fmd.DemoteMasterPosition, nil
return fmd.CurrentMasterPosition, nil
}

// WaitMasterPos is part of the MysqlDaemon interface
Expand Down
4 changes: 1 addition & 3 deletions go/vt/mysqlctl/mysql_daemon.go
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Expand Up @@ -58,9 +58,7 @@ type MysqlDaemon interface {
SetMaster(ctx context.Context, masterHost string, masterPort int, slaveStopBefore bool, slaveStartAfter bool) error
WaitForReparentJournal(ctx context.Context, timeCreatedNS int64) error

// DemoteMaster waits for all current transactions to finish,
// and returns the current replication position. It will not
// change the read_only state of the server.
// Deprecated: use MasterPosition() instead
DemoteMaster() (mysql.Position, error)

WaitMasterPos(context.Context, mysql.Position) error
Expand Down
11 changes: 1 addition & 10 deletions go/vt/mysqlctl/reparent.go
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Expand Up @@ -90,17 +90,8 @@ func (mysqld *Mysqld) WaitForReparentJournal(ctx context.Context, timeCreatedNS
}
}

// DemoteMaster will gracefully demote a master mysql instance to read only.
// If the master is still alive, then we need to demote it gracefully
// make it read-only, flush the writes and get the position
// Deprecated: use mysqld.MasterPosition() instead
func (mysqld *Mysqld) DemoteMaster() (rp mysql.Position, err error) {
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@dasl- dasl- Apr 30, 2019 •
edited
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if you approve of this idea, we could even get rid of the DemoteMaster method and associated RPC calls, since this becomes just a wrapper around MasterPosition.

We can use the MasterPosition RPC definitions instead. I am not sure how to update the protobuf definitions everywhere though...

cmds := []string{
"FLUSH TABLES WITH READ LOCK",
"UNLOCK TABLES",
}
if err = mysqld.ExecuteSuperQueryList(context.TODO(), cmds); err != nil {
return rp, err
}
return mysqld.MasterPosition()
}

Expand Down
4 changes: 2 additions & 2 deletions go/vt/vttablet/tabletmanager/rpc_replication.go
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Expand Up @@ -364,9 +364,9 @@ func (agent *ActionAgent) DemoteMaster(ctx context.Context) (string, error) {
return "", err
}

pos, err := agent.MysqlDaemon.DemoteMaster()
pos, err := agent.MysqlDaemon.MasterPosition()
if err != nil {
// if DemoteMaster failed, undo all the steps before
// if MasterPosition failed, undo all the steps before
// 1. set server back to read-only false
// setting read_only OFF will also set super_read_only OFF if it was set
if err1 := agent.MysqlDaemon.SetReadOnly(false); err1 != nil {
Expand Down
8 changes: 4 additions & 4 deletions go/vt/wrangler/testlib/planned_reparent_shard_test.go
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Expand Up @@ -75,7 +75,7 @@ func TestPlannedReparentShardNoMasterProvided(t *testing.T) {
// old master
oldMaster.FakeMysqlDaemon.ReadOnly = false
oldMaster.FakeMysqlDaemon.Replicating = false
oldMaster.FakeMysqlDaemon.DemoteMasterPosition = newMaster.FakeMysqlDaemon.WaitMasterPosition
oldMaster.FakeMysqlDaemon.CurrentMasterPosition = newMaster.FakeMysqlDaemon.WaitMasterPosition
oldMaster.FakeMysqlDaemon.SetMasterInput = topoproto.MysqlAddr(newMaster.Tablet)
oldMaster.FakeMysqlDaemon.ExpectedExecuteSuperQueryList = []string{
"FAKE SET MASTER",
Expand Down Expand Up @@ -181,7 +181,7 @@ func TestPlannedReparentShard(t *testing.T) {
// old master
oldMaster.FakeMysqlDaemon.ReadOnly = false
oldMaster.FakeMysqlDaemon.Replicating = false
oldMaster.FakeMysqlDaemon.DemoteMasterPosition = newMaster.FakeMysqlDaemon.WaitMasterPosition
oldMaster.FakeMysqlDaemon.CurrentMasterPosition = newMaster.FakeMysqlDaemon.WaitMasterPosition
oldMaster.FakeMysqlDaemon.SetMasterInput = topoproto.MysqlAddr(newMaster.Tablet)
oldMaster.FakeMysqlDaemon.ExpectedExecuteSuperQueryList = []string{
"FAKE SET MASTER",
Expand Down Expand Up @@ -328,7 +328,7 @@ func TestPlannedReparentShardPromoteSlaveFail(t *testing.T) {
oldMaster.FakeMysqlDaemon.ReadOnly = false
oldMaster.FakeMysqlDaemon.Replicating = false
// set to incorrect value to make promote fail on WaitForMasterPos
oldMaster.FakeMysqlDaemon.DemoteMasterPosition = newMaster.FakeMysqlDaemon.PromoteSlaveResult
oldMaster.FakeMysqlDaemon.CurrentMasterPosition = newMaster.FakeMysqlDaemon.PromoteSlaveResult
oldMaster.FakeMysqlDaemon.SetMasterInput = topoproto.MysqlAddr(newMaster.Tablet)
oldMaster.FakeMysqlDaemon.ExpectedExecuteSuperQueryList = []string{
"FAKE SET MASTER",
Expand Down Expand Up @@ -424,7 +424,7 @@ func TestPlannedReparentShardPromoteSlaveTimeout(t *testing.T) {
// old master
oldMaster.FakeMysqlDaemon.ReadOnly = false
oldMaster.FakeMysqlDaemon.Replicating = false
oldMaster.FakeMysqlDaemon.DemoteMasterPosition = newMaster.FakeMysqlDaemon.WaitMasterPosition
oldMaster.FakeMysqlDaemon.CurrentMasterPosition = newMaster.FakeMysqlDaemon.WaitMasterPosition
oldMaster.FakeMysqlDaemon.SetMasterInput = topoproto.MysqlAddr(newMaster.Tablet)
oldMaster.FakeMysqlDaemon.ExpectedExecuteSuperQueryList = []string{
"FAKE SET MASTER",
Expand Down