diff --git a/prepare_stmt.go b/prepare_stmt.go
index 0f112a7f..e017bb23 100644
--- a/prepare_stmt.go
+++ b/prepare_stmt.go
@@ -60,6 +60,7 @@ func (db *PreparedStmtDB) ExecContext(ctx context.Context, query string, args ..
 		return stmt.ExecContext(ctx, args...)
 	} else {
 		db.mux.Lock()
+		stmt.Close()
 		delete(db.Stmts, query)
 		db.mux.Unlock()
 	}
@@ -72,6 +73,7 @@ func (db *PreparedStmtDB) QueryContext(ctx context.Context, query string, args .
 		return stmt.QueryContext(ctx, args...)
 	} else {
 		db.mux.Lock()
+		stmt.Close()
 		delete(db.Stmts, query)
 		db.mux.Unlock()
 	}
@@ -84,6 +86,7 @@ func (db *PreparedStmtDB) QueryRowContext(ctx context.Context, query string, arg
 		return stmt.QueryRowContext(ctx, args...)
 	} else {
 		db.mux.Lock()
+		stmt.Close()
 		delete(db.Stmts, query)
 		db.mux.Unlock()
 	}
@@ -101,6 +104,7 @@ func (tx *PreparedStmtTX) ExecContext(ctx context.Context, query string, args ..
 		return tx.Tx.Stmt(stmt).ExecContext(ctx, args...)
 	} else {
 		tx.PreparedStmtDB.mux.Lock()
+		stmt.Close()
 		delete(tx.PreparedStmtDB.Stmts, query)
 		tx.PreparedStmtDB.mux.Unlock()
 	}
@@ -113,6 +117,7 @@ func (tx *PreparedStmtTX) QueryContext(ctx context.Context, query string, args .
 		return tx.Tx.Stmt(stmt).QueryContext(ctx, args...)
 	} else {
 		tx.PreparedStmtDB.mux.Lock()
+		stmt.Close()
 		delete(tx.PreparedStmtDB.Stmts, query)
 		tx.PreparedStmtDB.mux.Unlock()
 	}
@@ -125,6 +130,7 @@ func (tx *PreparedStmtTX) QueryRowContext(ctx context.Context, query string, arg
 		return tx.Tx.Stmt(stmt).QueryRowContext(ctx, args...)
 	} else {
 		tx.PreparedStmtDB.mux.Lock()
+		stmt.Close()
 		delete(tx.PreparedStmtDB.Stmts, query)
 		tx.PreparedStmtDB.mux.Unlock()
 	}
diff --git a/tests/go.mod b/tests/go.mod
index c467f34b..3b17feac 100644
--- a/tests/go.mod
+++ b/tests/go.mod
@@ -6,11 +6,11 @@ require (
 	github.com/google/uuid v1.1.1
 	github.com/jinzhu/now v1.1.1
 	github.com/lib/pq v1.6.0
-	gorm.io/driver/mysql v0.2.7
-	gorm.io/driver/postgres v0.2.4
+	gorm.io/driver/mysql v0.2.8
+	gorm.io/driver/postgres v0.2.5
 	gorm.io/driver/sqlite v1.0.8
 	gorm.io/driver/sqlserver v0.2.4
-	gorm.io/gorm v0.2.9
+	gorm.io/gorm v0.2.19
 )
 
 replace gorm.io/gorm => ../
diff --git a/tests/tests_test.go b/tests/tests_test.go
index fa8bad5c..9484b897 100644
--- a/tests/tests_test.go
+++ b/tests/tests_test.go
@@ -54,7 +54,10 @@ func OpenTestConnection() (db *gorm.DB, err error) {
 		if dbDSN == "" {
 			dbDSN = "user=gorm password=gorm DB.name=gorm port=9920 sslmode=disable TimeZone=Asia/Shanghai"
 		}
-		db, err = gorm.Open(postgres.Open(dbDSN), &gorm.Config{})
+		db, err = gorm.Open(postgres.New(postgres.Config{
+			DSN:                  dbDSN,
+			PreferSimpleProtocol: true,
+		}), &gorm.Config{})
 	case "sqlserver":
 		// CREATE LOGIN gorm WITH PASSWORD = 'LoremIpsum86';
 		// CREATE DATABASE gorm;