Merge pull request #75 from github/dynamic-throttle-control-replicas

supporting interactive command throttle-control-replicas

Author: Shlomi Noach

build.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 #
 #
-RELEASE_VERSION="0.9.5"
+RELEASE_VERSION="0.9.6"
 
 buildpath=/tmp/gh-ost
 target=gh-ost

doc/interactive-commands.md

@@ -16,11 +16,16 @@ Both interfaces may serve at the same time. Both respond to simple text command,
 
 - `help`: shows a brief list of available commands
 - `status`: returns a status summary of migration progress and configuration
-- `throttle`: force migration suspend
-- `no-throttle`: cancel forced suspension (though other throttling reasons may still apply)
+replication lag on to determine throttling
 - `chunk-size=<newsize>`: modify the `chunk-size`; applies on next running copy-iteration
 - `max-load=<max-load-thresholds>`: modify the `max-load` config; applies on next running copy-iteration
   The `max-load` format must be: `some_status=<numeric-threshold>[,some_status=<numeric-threshold>...]`. For example: `Threads_running=50,threads_connected=1000`, and you would then write/echo `max-load=Threads_running=50,threads_connected=1000` to the socket.
+- `critical-load=<load>`: change critical load setting (exceeding given thresholds causes panic and abort)
+- `throttle-query`: change throttle query
+- `throttle-control-replicas`: change list of throttle-control replicas, these are replicas `gh-ost` will cehck
+- `throttle`: force migration suspend
+- `no-throttle`: cancel forced suspension (though other throttling reasons may still apply)
+- `panic`: immediately panic and abort operation
 
 ### Examples
 

go/base/context.go

@@ -169,6 +169,9 @@ func (this *MigrationContext) GetGhostTableName() string {
 
 // GetOldTableName generates the name of the "old" table, into which the original table is renamed.
 func (this *MigrationContext) GetOldTableName() string {
+	// if this.TestOnReplica {
+	// 	return fmt.Sprintf("_%s_tst", this.OriginalTableName)
+	// }
 	return fmt.Sprintf("_%s_old", this.OriginalTableName)
 }
 
@@ -361,6 +364,28 @@ func (this *MigrationContext) ReadCriticalLoad(criticalLoadList string) error {
 	return nil
 }
 
+func (this *MigrationContext) GetThrottleControlReplicaKeys() *mysql.InstanceKeyMap {
+	this.throttleMutex.Lock()
+	defer this.throttleMutex.Unlock()
+
+	keys := mysql.NewInstanceKeyMap()
+	keys.AddKeys(this.ThrottleControlReplicaKeys.GetInstanceKeys())
+	return keys
+}
+
+func (this *MigrationContext) ReadThrottleControlReplicaKeys(throttleControlReplicas string) error {
+	keys := mysql.NewInstanceKeyMap()
+	if err := keys.ReadCommaDelimitedList(throttleControlReplicas); err != nil {
+		return err
+	}
+
+	this.throttleMutex.Lock()
+	defer this.throttleMutex.Unlock()
+
+	this.ThrottleControlReplicaKeys = keys
+	return nil
+}
+
 // ApplyCredentials sorts out the credentials between the config file and the CLI flags
 func (this *MigrationContext) ApplyCredentials() {
 	this.configMutex.Lock()

go/cmd/gh-ost/main.go

@@ -153,7 +153,7 @@ func main() {
 	if err := migrationContext.ReadConfigFile(); err != nil {
 		log.Fatale(err)
 	}
-	if err := migrationContext.ThrottleControlReplicaKeys.ReadCommaDelimitedList(*throttleControlReplicas); err != nil {
+	if err := migrationContext.ReadThrottleControlReplicaKeys(*throttleControlReplicas); err != nil {
 		log.Fatale(err)
 	}
 	if err := migrationContext.ReadMaxLoad(*maxLoad); err != nil {

go/logic/migrator.go

@@ -659,15 +659,16 @@ func (this *Migrator) onServerCommand(command string, writer *bufio.Writer) (err
 	case "help":
 		{
 			fmt.Fprintln(writer, `available commands:
-status                 # Print a status message
-chunk-size=<newsize>   # Set a new chunk-size
-critical-load=<load>   # Set a new set of max-load thresholds
-max-load=<load>        # Set a new set of max-load thresholds
-throttle-query=<query> # Set a new throttle-query
-throttle               # Force throttling
-no-throttle            # End forced throttling (other throttling may still apply)
-panic                  # panic and quit without cleanup
-help                   # This message
+status                               # Print a status message
+chunk-size=<newsize>                 # Set a new chunk-size
+critical-load=<load>                 # Set a new set of max-load thresholds
+max-load=<load>                      # Set a new set of max-load thresholds
+throttle-query=<query>               # Set a new throttle-query
+throttle-control-replicas=<replicas> #
+throttle                             # Force throttling
+no-throttle                          # End forced throttling (other throttling may still apply)
+panic                                # panic and quit without cleanup
+help                                 # This message
 `)
 		}
 	case "info", "status":
@@ -703,6 +704,15 @@ help                   # This message
 			this.migrationContext.SetThrottleQuery(arg)
 			this.printStatus(ForcePrintStatusAndHint, writer)
 		}
+	case "throttle-control-replicas":
+		{
+			if err := this.migrationContext.ReadThrottleControlReplicaKeys(arg); err != nil {
+				fmt.Fprintf(writer, "%s\n", err.Error())
+				return log.Errore(err)
+			}
+			fmt.Fprintf(writer, "%s\n", this.migrationContext.GetThrottleControlReplicaKeys().ToCommaDelimitedList())
+			this.printStatus(ForcePrintStatusAndHint, writer)
+		}
 	case "throttle", "pause", "suspend":
 		{
 			atomic.StoreInt64(&this.migrationContext.ThrottleCommandedByUser, 1)