adding code to main

Author: BarShauli555

go/cmd/gh-ost/main.go

@@ -105,17 +105,18 @@ func main() {
 	flag.BoolVar(&migrationContext.AssumeRBR, "assume-rbr", false, "set to 'true' when you know for certain your server uses 'ROW' binlog_format. gh-ost is unable to tell, event after reading binlog_format, whether the replication process does indeed use 'ROW', and restarts replication to be certain RBR setting is applied. Such operation requires SUPER privileges which you might not have. Setting this flag avoids restarting replication and you can proceed to use gh-ost without SUPER privileges")
 	flag.BoolVar(&migrationContext.CutOverExponentialBackoff, "cut-over-exponential-backoff", false, "Wait exponentially longer intervals between failed cut-over attempts. Wait intervals obey a maximum configurable with 'exponential-backoff-max-interval').")
 	exponentialBackoffMaxInterval := flag.Int64("exponential-backoff-max-interval", 64, "Maximum number of seconds to wait between attempts when performing various operations with exponential backoff.")
-	chunkSize := flag.Int64("chunk-size", 1000, "amount of rows to handle in each iteration (allowed range: 10-100,000)")
+	chunkSize := flag.Int64("chunk-size", 100, "amount of rows to handle in each iteration (allowed range: 10-100,000)")
 	dmlBatchSize := flag.Int64("dml-batch-size", 10, "batch size for DML events to apply in a single transaction (range 1-100)")
 	defaultRetries := flag.Int64("default-retries", 60, "Default number of retries for various operations before panicking")
 	cutOverLockTimeoutSeconds := flag.Int64("cut-over-lock-timeout-seconds", 3, "Max number of seconds to hold locks on tables while attempting to cut-over (retry attempted when lock exceeds timeout)")
-	niceRatio := flag.Float64("nice-ratio", 0, "force being 'nice', imply sleep time per chunk time; range: [0.0..100.0]. Example values: 0 is aggressive. 1: for every 1ms spent copying rows, sleep additional 1ms (effectively doubling runtime); 0.7: for every 10ms spend in a rowcopy chunk, spend 7ms sleeping immediately after")
+	niceRatio := flag.Float64("nice-ratio", 1, "force being 'nice', imply sleep time per chunk time; range: [0.0..100.0]. Example values: 0 is aggressive. 1: for every 1ms spent copying rows, sleep additional 1ms (effectively doubling runtime); 0.7: for every 10ms spend in a rowcopy chunk, spend 7ms sleeping immediately after")
 
 	maxLagMillis := flag.Int64("max-lag-millis", 1500, "replication lag at which to throttle operation")
 	replicationLagQuery := flag.String("replication-lag-query", "", "Deprecated. gh-ost uses an internal, subsecond resolution query")
 	throttleControlReplicas := flag.String("throttle-control-replicas", "", "List of replicas on which to check for lag; comma delimited. Example: myhost1.com:3306,myhost2.com,myhost3.com:3307")
 	throttleQuery := flag.String("throttle-query", "", "when given, issued (every second) to check if operation should throttle. Expecting to return zero for no-throttle, >0 for throttle. Query is issued on the migrated server. Make sure this query is lightweight")
 	throttleHTTP := flag.String("throttle-http", "", "when given, gh-ost checks given URL via HEAD request; any response code other than 200 (OK) causes throttling; make sure it has low latency response")
+	copyWhereClause := flag.String("where-clause", "1=1", "added where clause for the insert query, filtering table rows")
 	flag.Int64Var(&migrationContext.ThrottleHTTPIntervalMillis, "throttle-http-interval-millis", 100, "Number of milliseconds to wait before triggering another HTTP throttle check")
 	flag.Int64Var(&migrationContext.ThrottleHTTPTimeoutMillis, "throttle-http-timeout-millis", 1000, "Number of milliseconds to use as an HTTP throttle check timeout")
 	ignoreHTTPErrors := flag.Bool("ignore-http-errors", false, "ignore HTTP connection errors during throttle check")
@@ -304,6 +305,7 @@ func main() {
 	migrationContext.SetThrottleHTTP(*throttleHTTP)
 	migrationContext.SetIgnoreHTTPErrors(*ignoreHTTPErrors)
 	migrationContext.SetDefaultNumRetries(*defaultRetries)
+	migrationContext.SetWhereClause(*copyWhereClause)
 	migrationContext.ApplyCredentials()
 	if err := migrationContext.SetupTLS(); err != nil {
 		migrationContext.Log.Fatale(err)