Add use_super_read_only back for v15->v19 migration

go/vt/vttablet/tabletmanager/rpc_replication.go

@@ -22,6 +22,7 @@ import (
  "strings"
  "time"
 
+ "github.com/spf13/pflag"
  "vitess.io/vitess/go/mysql/replication"
  "vitess.io/vitess/go/mysql/sqlerror"
  "vitess.io/vitess/go/protoutil"
@@ -30,13 +31,24 @@ import (
  "vitess.io/vitess/go/vt/log"
  "vitess.io/vitess/go/vt/mysqlctl"
  "vitess.io/vitess/go/vt/proto/vtrpc"
+ "vitess.io/vitess/go/vt/servenv"
  "vitess.io/vitess/go/vt/topo/topoproto"
  "vitess.io/vitess/go/vt/vterrors"
 
  replicationdatapb "vitess.io/vitess/go/vt/proto/replicationdata"
  topodatapb "vitess.io/vitess/go/vt/proto/topodata"
 )
 
+var setSuperReadOnly bool
+
+func registerReplicationFlags(fs *pflag.FlagSet) {
+ fs.BoolVar(&setSuperReadOnly, "use_super_read_only", setSuperReadOnly, "Set super_read_only flag when performing planned failover.")
+}
+
+func init() {
+ servenv.OnParseFor("vttablet", registerReplicationFlags)
+}
+
 // ReplicationStatus returns the replication status
 func (tm *TabletManager) ReplicationStatus(ctx context.Context) (*replicationdatapb.Status, error) {
  if err := tm.waitForGrantsToHaveApplied(ctx); err != nil {
@@ -528,10 +540,16 @@ func (tm *TabletManager) demotePrimary(ctx context.Context, revertPartialFailure
  // set MySQL to super_read_only mode. If we are already super_read_only because of a
  // previous demotion, or because we are not primary anyway, this should be
  // idempotent.
- if _, err := tm.MysqlDaemon.SetSuperReadOnly(true); err != nil {
- if sqlErr, ok := err.(*sqlerror.SQLError); ok && sqlErr.Number() == sqlerror.ERUnknownSystemVariable {
- log.Warningf("server does not know about super_read_only, continuing anyway...")
- } else {
+ if setSuperReadOnly {
+ if _, err := tm.MysqlDaemon.SetSuperReadOnly(true); err != nil {
+ if sqlErr, ok := err.(*sqlerror.SQLError); ok && sqlErr.Number() == sqlerror.ERUnknownSystemVariable {
+ log.Warningf("server does not know about super_read_only, continuing anyway...")
+ } else {
+ return nil, err
+ }
+ }
+ } else {
+ if err := tm.MysqlDaemon.SetReadOnly(true); err != nil {
  return nil, err
  }
  }