expression: implement vectorized evaluation for builtinCastStringAsTimeSig (#12947)

expression/builtin_cast_vec.go

@@ -1092,11 +1092,44 @@ func (b *builtinCastStringAsDecimalSig) vecEvalDecimal(input *chunk.Chunk, resul
 }
 
 func (b *builtinCastStringAsTimeSig) vectorized() bool {
-	return false
+	return true
 }
 
 func (b *builtinCastStringAsTimeSig) vecEvalTime(input *chunk.Chunk, result *chunk.Column) error {
-	return errors.Errorf("not implemented")
+	n := input.NumRows()
+	buf, err := b.bufAllocator.get(types.ETString, n)
+	if err != nil {
+		return err
+	}
+	defer b.bufAllocator.put(buf)
+	if err := b.args[0].VecEvalString(b.ctx, input, buf); err != nil {
+		return err
+	}
+
+	result.ResizeTime(n, false)
+	result.MergeNulls(buf)
+	times := result.Times()
+	stmtCtx := b.ctx.GetSessionVars().StmtCtx
+	fsp := int8(b.tp.Decimal)
+	for i := 0; i < n; i++ {
+		if result.IsNull(i) {
+			continue
+		}
+		tm, err := types.ParseTime(stmtCtx, buf.GetString(i), b.tp.Tp, fsp)
+		if err != nil {
+			if err = handleInvalidTimeError(b.ctx, err); err != nil {
+				return err
+			}
+			result.SetNull(i, true)
+			continue
+		}
+		times[i] = tm
+		if b.tp.Tp == mysql.TypeDate {
+			// Truncate hh:mm:ss part if the type is Date.
+			times[i].Time = types.FromDate(tm.Time.Year(), tm.Time.Month(), tm.Time.Day(), 0, 0, 0, 0)
+		}
+	}
+	return nil
 }
 
 func (b *builtinCastDecimalAsIntSig) vectorized() bool {

expression/builtin_cast_vec_test.go

@@ -59,6 +59,12 @@ var vecBuiltinCastCases = map[string][]vecExprBenchCase{
 		{retEvalType: types.ETDatetime, childrenTypes: []types.EvalType{types.ETReal}},
 		{retEvalType: types.ETDatetime, childrenTypes: []types.EvalType{types.ETDecimal}},
 		{retEvalType: types.ETDatetime, childrenTypes: []types.EvalType{types.ETInt}},
+		{retEvalType: types.ETDatetime, childrenTypes: []types.EvalType{types.ETString},
+			geners: []dataGenerator{
+				&dataTimeStrGener{},
+				&timeStrGener{},
+				&dataStrGener{},
+			}},
 	},
 }