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Add --test-on-replica-skip-replica-stop flag

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This commit is contained in:
Paulo Bittencourt 2016-08-19 17:34:08 -04:00
parent a62f9e0754
commit 2e43718ef3
3 changed files with 16 additions and 38 deletions
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2
go/base/context.go
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@ -85,7 +85,7 @@ type MigrationContext struct {
Noop bool
TestOnReplica bool
MigrateOnReplica bool
ManualReplicationControl bool
TestOnReplicaSkipReplicaStop bool
OkToDropTable bool
InitiallyDropOldTable bool
InitiallyDropGhostTable bool

12
go/cmd/gh-ost/main.go
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@ -60,8 +60,8 @@ func main() {
flag.BoolVar(&migrationContext.SkipRenamedColumns, "skip-renamed-columns", false, "in case your `ALTER` statement renames columns, gh-ost will note that and offer its interpretation of the rename. By default gh-ost does not proceed to execute. This flag tells gh-ost to skip the renamed columns, i.e. to treat what gh-ost thinks are renamed columns as unrelated columns. NOTE: you may lose column data")
executeFlag := flag.Bool("execute", false, "actually execute the alter & migrate the table. Default is noop: do some tests and exit")
testOnReplicaWithManualReplicationControl := flag.Bool("test-on-replica-manual-replication-control", false, "Same as --test-on-replica, but waits for replication to be stopped, instead of stopping it automatically. (Useful in RDS.)")
flag.BoolVar(&migrationContext.TestOnReplica, "test-on-replica", false, "Have the migration run on a replica, not on the master. At the end of migration replication is stopped, and tables are swapped and immediately swap-revert. Replication remains stopped and you can compare the two tables for building trust")
flag.BoolVar(&migrationContext.TestOnReplicaSkipReplicaStop, "test-on-replica-skip-replica-stop", false, "When --test-on-replica is enabled, do not issue commands stop replication (requires --test-on-replica)")
flag.BoolVar(&migrationContext.MigrateOnReplica, "migrate-on-replica", false, "Have the migration run on a replica, not on the master. This will do the full migration on the replica including cut-over (as opposed to --test-on-replica)")
flag.BoolVar(&migrationContext.OkToDropTable, "ok-to-drop-table", false, "Shall the tool drop the old table at end of operation. DROPping tables can be a long locking operation, which is why I'm not doing it by default. I'm an online tool, yes?")
@ -150,13 +150,13 @@ func main() {
if migrationContext.SwitchToRowBinlogFormat && migrationContext.AssumeRBR {
log.Fatalf("--switch-to-rbr and --assume-rbr are mutually exclusive")
}
if *testOnReplicaWithManualReplicationControl {
if migrationContext.TestOnReplica {
log.Fatalf("--test-on-replica-manual-replication-control and --test-on-replica are mutually exclusive")
if migrationContext.TestOnReplicaSkipReplicaStop {
if !migrationContext.TestOnReplica {
log.Fatalf("--test-on-replica-skip-replica-stop requires --test-on-replica to be enabled")
}
migrationContext.TestOnReplica = true
migrationContext.ManualReplicationControl = true
log.Warning("--test-on-replica-skip-replica-stop enabled. We will not stop replication before cut-over. Ensure you have a plugin that does this.")
}
switch *cutOver {
case "atomic", "default", "":
migrationContext.CutOverType = base.CutOverAtomic

26
go/logic/applier.go
View File

@ -566,32 +566,10 @@ func (this *Applier) StartSlaveSQLThread() error {
return nil
}
func (this *Applier) isReplicationStopped() bool {
query := `show slave status`
replicationStopped := false
err := sqlutils.QueryRowsMap(this.db, query, func(rowMap sqlutils.RowMap) error {
replicationStopped = rowMap["Slave_IO_Running"].String == "No" && rowMap["Slave_SQL_Running"].String == "No"
return nil
})
if err != nil {
return false
}
return replicationStopped
}
// StopReplication is used by `--test-on-replica` and stops replication.
func (this *Applier) StopReplication() error {
if this.migrationContext.ManualReplicationControl {
for {
log.Info("Waiting for replication to stop...")
if this.isReplicationStopped() {
log.Info("Replication stopped.")
break
}
time.Sleep(5 * time.Second)
}
if this.migrationContext.TestOnReplicaSkipReplicaStop {
log.Warningf("--test-on-replica-skip-replica-stop enabled, we are not stopping replication.")
} else {
if err := this.StopSlaveIOThread(); err != nil {
return err