From 4155b3b80838221d327ce2e24eb21e5b77519a78 Mon Sep 17 00:00:00 2001
From: tsthght <781181214@qq.com>
Date: Fri, 18 Oct 2019 15:59:19 +0800
Subject: [PATCH] expression: implement vectorized evaluation for
 'builtinCastTimeAsJSONSig' (#12795)

---
 expression/builtin_cast_vec.go      | 28 ++++++++++++++++++++++++++--
 expression/builtin_cast_vec_test.go |  1 +
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/expression/builtin_cast_vec.go b/expression/builtin_cast_vec.go
index 4b8dbcfcfed21..ed14a1e6fb446 100644
--- a/expression/builtin_cast_vec.go
+++ b/expression/builtin_cast_vec.go
@@ -149,11 +149,35 @@ func (b *builtinCastRealAsRealSig) vectorized() bool {
 }
 
 func (b *builtinCastTimeAsJSONSig) vectorized() bool {
-	return false
+	return true
 }
 
 func (b *builtinCastTimeAsJSONSig) vecEvalJSON(input *chunk.Chunk, result *chunk.Column) error {
-	return errors.Errorf("not implemented")
+	n := input.NumRows()
+	buf, err := b.bufAllocator.get(types.ETDatetime, n)
+	if err != nil {
+		return err
+	}
+	defer b.bufAllocator.put(buf)
+	if err = b.args[0].VecEvalTime(b.ctx, input, buf); err != nil {
+		return err
+	}
+
+	result.ReserveJSON(n)
+	tms := buf.Times()
+	for i := 0; i < n; i++ {
+		if buf.IsNull(i) {
+			result.AppendNull()
+			continue
+		}
+
+		tp := tms[i].Type
+		if tp == mysql.TypeDatetime || tp == mysql.TypeTimestamp {
+			tms[i].Fsp = types.MaxFsp
+		}
+		result.AppendJSON(json.CreateBinary(tms[i].String()))
+	}
+	return nil
 }
 
 func (b *builtinCastRealAsStringSig) vectorized() bool {
diff --git a/expression/builtin_cast_vec_test.go b/expression/builtin_cast_vec_test.go
index 6496b1634c602..fce168c9fd9ef 100644
--- a/expression/builtin_cast_vec_test.go
+++ b/expression/builtin_cast_vec_test.go
@@ -50,6 +50,7 @@ var vecBuiltinCastCases = map[string][]vecExprBenchCase{
 		{retEvalType: types.ETDuration, childrenTypes: []types.EvalType{types.ETDuration}},
 		{retEvalType: types.ETJson, childrenTypes: []types.EvalType{types.ETInt}},
 		{retEvalType: types.ETJson, childrenTypes: []types.EvalType{types.ETReal}},
+		{retEvalType: types.ETJson, childrenTypes: []types.EvalType{types.ETDatetime}},
 		{retEvalType: types.ETJson, childrenTypes: []types.EvalType{types.ETJson}},
 		{retEvalType: types.ETJson, childrenTypes: []types.EvalType{types.ETDecimal}},
 	},