Address PR feedback

Author: morgo

go/logic/applier_test.go

@@ -182,5 +182,4 @@ func TestApplierInstantDDL(t *testing.T) {
 		stmt := applier.generateInstantDDLQuery()
 		test.S(t).ExpectEquals(stmt, "ALTER /* gh-ost */ TABLE `test`.`mytable` ADD INDEX (foo), ALGORITHM=INSTANT")
 	})
-
 }

go/logic/migrator.go

@@ -351,6 +351,15 @@ func (this *Migrator) Migrate() (err error) {
 	if err := this.initiateInspector(); err != nil {
 		return err
 	}
+	if err := this.initiateStreaming(); err != nil {
+		return err
+	}
+	if err := this.initiateApplier(); err != nil {
+		return err
+	}
+	if err := this.createFlagFiles(); err != nil {
+		return err
+	}
 	// In MySQL 8.0 (and possibly earlier) some DDL statements can be applied instantly.
 	// Attempt to do this if AttemptInstantDDL is set.
 	if this.migrationContext.AttemptInstantDDL {
@@ -363,16 +372,6 @@ func (this *Migrator) Migrate() (err error) {
 		}
 	}
 
-	if err := this.initiateStreaming(); err != nil {
-		return err
-	}
-	if err := this.initiateApplier(); err != nil {
-		return err
-	}
-	if err := this.createFlagFiles(); err != nil {
-		return err
-	}
-
 	initialLag, _ := this.inspector.getReplicationLag()
 	this.migrationContext.Log.Infof("Waiting for ghost table to be migrated. Current lag is %+v", initialLag)
 	<-this.ghostTableMigrated
@@ -750,10 +749,6 @@ func (this *Migrator) initiateServer() (err error) {
 // using a ALGORITHM=INSTANT assertion. If this fails, it will return an error,
 // in which case the original algorithm should be used.
 func (this *Migrator) attemptInstantDDL() (err error) {
-	this.applier = NewApplier(this.migrationContext)
-	if err := this.applier.InitDBConnections(); err != nil {
-		return err
-	}
 	return this.applier.AttemptInstantDDL()
 }