Better memory usage

raphaelvigee · Nov 19, 2020 · e40b45a · e40b45a
1 parent 9fa411e
commit e40b45a
Show file tree

Hide file tree

Showing 3 changed files with 11 additions and 10 deletions.
diff --git a/cursor.go b/cursor.go
@@ -45,9 +45,9 @@ func (r *Paginator) Cursor(encoded string, typ CursorType, limit int) (Cursor, e
 }
 
 func (r *Paginator) cursorString(v map[string]interface{}) string {
-	valuesArr := make([]interface{}, 0)
-	for _, column := range r.Columns {
-		valuesArr = append(valuesArr, v[column.Name])
+	valuesArr := make([]interface{}, len(r.Columns))
+	for i, column := range r.Columns {
+		valuesArr[i] = v[column.Name]
 	}
 
 	data, err := msgpack.Marshal(valuesArr)

diff --git a/gorm_map.go b/gorm_map.go
@@ -52,7 +52,7 @@ func rowMap(rows *sql.Rows) (map[string]interface{}, error) {
 
 	columns := make([]interface{}, len(cols))
 	columnPointers := make([]interface{}, len(cols))
-	for i, _ := range columns {
+	for i := range columns {
 		columnPointers[i] = &columns[i]
 	}
 

diff --git a/paginator.go b/paginator.go
@@ -48,7 +48,7 @@ func fork(tx *gorm.DB) *gorm.DB {
 func (r *Paginator) generateCondition(typ CursorType, values map[string]interface{}, op Op) (string, []interface{}) {
 	s := "1=0"
 
-	args := make([]interface{}, 0)
+	args := make([]interface{}, 0, len(r.Columns)*2)
 
 	for i := len(r.Columns) - 1; i >= 0; i-- {
 		column := r.Columns[i]
@@ -75,12 +75,12 @@ func (r *Paginator) Paginate(c Cursor, tx *gorm.DB) (*Response, error) {
 	limit := c.Limit
 
 	otx := fork(tx)
-	columnNames := make([]string, 0)
-	for _, column := range r.Columns {
+	columnNames := make([]string, len(r.Columns))
+	for i, column := range r.Columns {
 		order := column.Order(c.Type)
 
 		otx = otx.Order(fmt.Sprintf("%v %v", column.Name, order))
-		columnNames = append(columnNames, column.Name)
+		columnNames[i] = column.Name
 	}
 
 	tx.Logger.Info(tx.Statement.Context, "columns: %v", columnNames)
@@ -153,8 +153,9 @@ func (r *Paginator) Paginate(c Cursor, tx *gorm.DB) (*Response, error) {
 	var sc, ec string
 	var cursors []string
 	if len(nvalues) > 0 {
-		for _, v := range nvalues {
-			cursors = append(cursors, r.cursorString(v))
+		cursors = make([]string, len(nvalues))
+		for i, v := range nvalues {
+			cursors[i] = r.cursorString(v)
 		}
 
 		mi := len(nvalues) - 1