spanner-annotationsimpls-fixes (#102622)

* Fix DELETE statements.
* Reset sequence generator when truncating tables.
* Quote "at", since it's a keyword in Spanner.

pkg/util/xorm/sequence.go

@@ -19,6 +19,10 @@ func newSequenceGenerator(db *sql.DB) *sequenceGenerator {
 	}
 }
 
+func (sg *sequenceGenerator) Reset() {
+	// Nothing to do. This generator always uses state from DB.
+}
+
 func (sg *sequenceGenerator) Next(ctx context.Context, table, column string) (int64, error) {
 	// Current implementation fetches new value for each Next call.
 	key := fmt.Sprintf("%s:%s", table, column)

pkg/util/xorm/sequence_inmem.go

@@ -18,6 +18,13 @@ func newInMemSequenceGenerator() *inMemSequenceGenerator {
 	}
 }
 
+func (g *inMemSequenceGenerator) Reset() {
+	g.sequencesMu.Lock()
+	defer g.sequencesMu.Unlock()
+
+	g.nextValues = make(map[string]int)
+}
+
 func (g *inMemSequenceGenerator) Next(_ context.Context, table, column string) (int64, error) {
 	if table == "migration_log" {
 		// Don't use sequential IDs for migration log entries, as we don't clean up migration_log table between tests,

pkg/util/xorm/xorm.go

@@ -127,8 +127,15 @@ func NewEngine(driverName string, dataSourceName string) (*Engine, error) {
 	return engine, nil
 }
 
+func (engine *Engine) ResetSequenceGenerator() {
+	if engine.sequenceGenerator != nil {
+		engine.sequenceGenerator.Reset()
+	}
+}
+
 type SequenceGenerator interface {
 	Next(ctx context.Context, table, column string) (int64, error)
+	Reset()
 }
 
 type DialectExt interface {