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Improve Rows scan performance

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ScanContext reused between rows.Scan calls.
Simplified assign value logic.
Use complex destination for Rows test.
This commit is contained in:
go-jet 2022-02-04 12:31:08 +01:00
parent 4f29960378
commit c10244aeab
5 changed files with 114 additions and 84 deletions
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23
qrm/scan_context.go
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@ -7,7 +7,9 @@ import (
"strings"
)
type scanContext struct {
// ScanContext contains information about current row processed, mapping from the row to the
// destination types and type grouping information.
type ScanContext struct {
rowNum int64
row []interface{}
uniqueDestObjectsMap map[string]int
@ -16,7 +18,8 @@ type scanContext struct {
typeInfoMap map[string]typeInfo
}
func newScanContext(rows *sql.Rows) (*scanContext, error) {
// NewScanContext creates new ScanContext from rows
func NewScanContext(rows *sql.Rows) (*ScanContext, error) {
aliases, err := rows.Columns()
if err != nil {
@ -42,7 +45,7 @@ func newScanContext(rows *sql.Rows) (*scanContext, error) {
commonIdentToColumnIndex[commonIdentifier] = i
}
return &scanContext{
return &ScanContext{
row: createScanSlice(len(columnTypes)),
uniqueDestObjectsMap: make(map[string]int),
@ -74,7 +77,7 @@ type fieldMapping struct {
implementsScanner bool
}
func (s *scanContext) getTypeInfo(structType reflect.Type, parentField *reflect.StructField) typeInfo {
func (s *ScanContext) getTypeInfo(structType reflect.Type, parentField *reflect.StructField) typeInfo {
typeMapKey := structType.String()
@ -120,7 +123,7 @@ type groupKeyInfo struct {
subTypes []groupKeyInfo
}
func (s *scanContext) getGroupKey(structType reflect.Type, structField *reflect.StructField) string {
func (s *ScanContext) getGroupKey(structType reflect.Type, structField *reflect.StructField) string {
mapKey := structType.Name()
@ -139,7 +142,7 @@ func (s *scanContext) getGroupKey(structType reflect.Type, structField *reflect.
return s.constructGroupKey(groupKeyInfo)
}
func (s *scanContext) constructGroupKey(groupKeyInfo groupKeyInfo) string {
func (s *ScanContext) constructGroupKey(groupKeyInfo groupKeyInfo) string {
if len(groupKeyInfo.indexes) == 0 && len(groupKeyInfo.subTypes) == 0 {
return fmt.Sprintf("|ROW:%d|", s.rowNum)
}
@ -161,7 +164,7 @@ func (s *scanContext) constructGroupKey(groupKeyInfo groupKeyInfo) string {
return groupKeyInfo.typeName + "(" + strings.Join(groupKeys, ",") + strings.Join(subTypesGroupKeys, ",") + ")"
}
func (s *scanContext) getGroupKeyInfo(
func (s *ScanContext) getGroupKeyInfo(
structType reflect.Type,
parentField *reflect.StructField,
typeVisited *typeStack) groupKeyInfo {
@ -210,7 +213,7 @@ func (s *scanContext) getGroupKeyInfo(
return ret
}
func (s *scanContext) typeToColumnIndex(typeName, fieldName string) int {
func (s *ScanContext) typeToColumnIndex(typeName, fieldName string) int {
var key string
if typeName != "" {
@ -228,7 +231,7 @@ func (s *scanContext) typeToColumnIndex(typeName, fieldName string) int {
return index
}
func (s *scanContext) rowElem(index int) interface{} {
func (s *ScanContext) rowElem(index int) interface{} {
cellValue := reflect.ValueOf(s.row[index])
if cellValue.IsValid() && !cellValue.IsNil() {
@ -238,7 +241,7 @@ func (s *scanContext) rowElem(index int) interface{} {
return nil
}
func (s *scanContext) rowElemValuePtr(index int) reflect.Value {
func (s *ScanContext) rowElemValuePtr(index int) reflect.Value {
rowElem := s.rowElem(index)
rowElemValue := reflect.ValueOf(rowElem)