addressed review comments

Signed-off-by: Harshit Gangal <[email protected]>

go/vt/vtgate/engine/fake_vcursor_test.go

@@ -275,10 +275,6 @@ func (t *noopVCursor) SetAutocommit(context.Context, bool) error {
 	panic("implement me")
 }
 
-func (t *noopVCursor) SetSessionForeignKeyChecks(ctx context.Context, foreignKeyChecks bool) error {
-	panic("implement me")
-}
-
 func (t *noopVCursor) SetClientFoundRows(context.Context, bool) error {
 	panic("implement me")
 }
@@ -747,10 +743,6 @@ func (f *loggingVCursor) SetAutocommit(context.Context, bool) error {
 	panic("implement me")
 }
 
-func (f *loggingVCursor) SetSessionForeignKeyChecks(ctx context.Context, foreignKeyChecks bool) error {
-	panic("implement me")
-}
-
 func (f *loggingVCursor) SetClientFoundRows(context.Context, bool) error {
 	panic("implement me")
 }

go/vt/vtgate/engine/primitive.go

@@ -154,7 +154,6 @@ type (
 
 		SetAutocommit(ctx context.Context, autocommit bool) error
 		SetClientFoundRows(context.Context, bool) error
-		SetSessionForeignKeyChecks(ctx context.Context, autocommit bool) error
 		SetSkipQueryPlanCache(context.Context, bool) error
 		SetSQLSelectLimit(int64) error
 		SetTransactionMode(vtgatepb.TransactionMode)

go/vt/vtgate/safe_session.go

@@ -573,25 +573,23 @@ func (session *SafeSession) TimeZone() *time.Location {
 }
 
 // ForeignKeyChecks returns the foreign_key_checks stored in system_variables map in the session.
-func (session *SafeSession) ForeignKeyChecks() (*bool, *string) {
+func (session *SafeSession) ForeignKeyChecks() *bool {
 	session.mu.Lock()
 	fkVal, ok := session.SystemVariables[sysvars.ForeignKeyChecks]
 	session.mu.Unlock()
 
 	if !ok {
-		return nil, nil
+		return nil
 	}
 	switch strings.ToLower(fkVal) {
 	case "off", "0":
-		fkCheckStr := "0"
 		fkCheckBool := false
-		return &fkCheckBool, &fkCheckStr
+		return &fkCheckBool
 	case "on", "1":
-		fkCheckStr := "1"
 		fkCheckBool := true
-		return &fkCheckBool, &fkCheckStr
+		return &fkCheckBool
 	}
-	return nil, nil
+	return nil
 }
 
 // SetOptions sets the options

go/vt/vtgate/vcursor_impl.go

@@ -43,7 +43,6 @@ import (
 	vtrpcpb "vitess.io/vitess/go/vt/proto/vtrpc"
 	"vitess.io/vitess/go/vt/sqlparser"
 	"vitess.io/vitess/go/vt/srvtopo"
-	"vitess.io/vitess/go/vt/sysvars"
 	"vitess.io/vitess/go/vt/topo"
 	topoprotopb "vitess.io/vitess/go/vt/topo/topoproto"
 	"vitess.io/vitess/go/vt/topotools"
@@ -832,16 +831,6 @@ func (vc *vcursorImpl) SetAutocommit(ctx context.Context, autocommit bool) error
 	return nil
 }
 
-// SetSessionForeignKeyChecks implements the SessionActions interface
-func (vc *vcursorImpl) SetSessionForeignKeyChecks(ctx context.Context, foreignKeyChecks bool) error {
-	if foreignKeyChecks {
-		vc.safeSession.SetSystemVariable(sysvars.ForeignKeyChecks, "1")
-	} else {
-		vc.safeSession.SetSystemVariable(sysvars.ForeignKeyChecks, "0")
-	}
-	return nil
-}
-
 // SetQueryTimeout implements the SessionActions interface
 func (vc *vcursorImpl) SetQueryTimeout(maxExecutionTime int64) {
 	vc.safeSession.QueryTimeout = maxExecutionTime
@@ -1365,7 +1354,7 @@ func (vc *vcursorImpl) UpdateForeignKeyChecksState(fkStateFromQuery *bool) {
 		return
 	}
 	// If the query doesn't have anything, then we consult the session state.
-	vc.fkChecksState, _ = vc.safeSession.ForeignKeyChecks()
+	vc.fkChecksState = vc.safeSession.ForeignKeyChecks()
 }
 
 // GetForeignKeyChecksState gets the stored foreign key checks state in the vcursor.