From 4798f340f83c1904e835d8da81e87d468d64c5d8 Mon Sep 17 00:00:00 2001
From: shihongzhi <shi65881583@gmail.com>
Date: Wed, 16 Oct 2019 20:34:55 +0800
Subject: [PATCH] expression: implement vectorized evaluation for
 `builtinRTrimSig` (#12736)

---
 expression/builtin_string_vec.go      | 27 +++++++++++++++++++++++++--
 expression/builtin_string_vec_test.go |  4 +++-
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/expression/builtin_string_vec.go b/expression/builtin_string_vec.go
index b4c996b501..65d381a1bc 100644
--- a/expression/builtin_string_vec.go
+++ b/expression/builtin_string_vec.go
@@ -638,11 +638,34 @@ func (b *builtinReverseBinarySig) vecEvalString(input *chunk.Chunk, result *chun
 }
 
 func (b *builtinRTrimSig) vectorized() bool {
-	return false
+	return true
 }
 
+// evalString evals a builtinRTrimSig
+// See https://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_rtrim
 func (b *builtinRTrimSig) vecEvalString(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.ReserveString(n)
+	for i := 0; i < n; i++ {
+		if buf.IsNull(i) {
+			result.AppendNull()
+			continue
+		}
+
+		str := buf.GetString(i)
+		result.AppendString(strings.TrimRight(str, spaceChars))
+	}
+
+	return nil
 }
 
 func (b *builtinStrcmpSig) vectorized() bool {
diff --git a/expression/builtin_string_vec_test.go b/expression/builtin_string_vec_test.go
index f314e6bf19..7be6ea5515 100644
--- a/expression/builtin_string_vec_test.go
+++ b/expression/builtin_string_vec_test.go
@@ -88,7 +88,9 @@ var vecBuiltinStringCases = map[string][]vecExprBenchCase{
 		{retEvalType: types.ETString, childrenTypes: []types.EvalType{types.ETString, types.ETString}, geners: []dataGenerator{&randLenStrGener{10, 20}, &randLenStrGener{5, 25}}},
 	},
 	ast.LTrim: {},
-	ast.RTrim: {},
+	ast.RTrim: {
+		{retEvalType: types.ETString, childrenTypes: []types.EvalType{types.ETString}, geners: []dataGenerator{&randSpaceStrGener{10, 100}}},
+	},
 	ast.Lpad: {
 		{
 			retEvalType:   types.ETString,