expression: implement vectorized evaluation for builtinPowSig

expression/bench_test.go

@@ -247,6 +247,24 @@ func (g *defaultGener) gen() interface{} {
 	return nil
 }
 
+// rangeRealGener is used to generate float64 items in [begin, end].
+type rangeRealGener struct {
+	begin float64
+	end float64
+	nullRation float64
+}
+
+func (g *rangeRealGener) gen() interface{} {
+	if rand.Float64() < g.nullRation {
+		return nil
+	}
+	if g.end <= g.begin {
+		g.begin = -100
+		g.end = 100
+	}
+	return rand.Float64() * (g.end - g.begin) + g.begin
+}
+
 // rangeInt64Gener is used to generate int64 items in [begin, end).
 type rangeInt64Gener struct {
 	begin int

expression/builtin_math_vec.go

@@ -14,7 +14,9 @@
 package expression
 
 import (
+	"fmt"
 	"math"
+	"strconv"
 
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/chunk"
@@ -223,3 +225,47 @@ func (b *builtinRoundDecSig) vecEvalDecimal(input *chunk.Chunk, result *chunk.Co
 func (b *builtinRoundDecSig) vectorized() bool {
 	return true
 }
+
+func (b *builtinPowSig) vecEvalReal(input *chunk.Chunk, result *chunk.Column) error {
+	n := input.NumRows()
+	buf1, err := b.bufAllocator.get(types.ETReal, n)
+	if err != nil {
+		return err
+	}
+	defer b.bufAllocator.put(buf1)
+	if err := b.args[0].VecEvalReal(b.ctx, input, buf1); err != nil {
+		return err
+	}
+
+	buf2, err := b.bufAllocator.get(types.ETReal, n)
+	if err != nil {
+		return err
+	}
+	defer b.bufAllocator.put(buf2)
+	if err := b.args[1].VecEvalReal(b.ctx, input, buf2); err != nil {
+		return err
+	}
+	x := buf1.Float64s()
+	y := buf2.Float64s()
+	result.ResizeFloat64(n, false)
+	f64s := result.Float64s()
+	for i := 0; i < n; i++ {
+		if (buf1.IsNull(i) || buf2.IsNull(i)) {
+			result.SetNull(i, true)
+			continue
+		}
+		power := math.Pow(x[i], y[i])
+		if math.IsInf(power, -1) || math.IsInf(power, 1) || math.IsNaN(power) {
+			err := types.ErrOverflow.GenWithStackByArgs("DOUBLE", fmt.Sprintf("pow(%s, %s)", strconv.FormatFloat(x[i], 'f', -1, 64), strconv.FormatFloat(y[i], 'f', -1, 64)))
+			b.ctx.GetSessionVars().StmtCtx.HandleOverflow(err, err)
+			f64s[i] = 0
+		} else {
+			f64s[i] = power
+		}
+	}
+	return nil
+}
+
+func (b *builtinPowSig) vectorized() bool {
+	return true
+}

expression/builtin_math_vec_test.go

@@ -49,6 +49,10 @@ var vecBuiltinMathCases = map[string][]vecExprBenchCase{
 	ast.Round: {
 		{types.ETDecimal, []types.EvalType{types.ETDecimal}, nil},
 	},
+	ast.Pow: {
+		{types.ETReal, []types.EvalType{types.ETReal, types.ETReal}, []dataGenerator{&rangeRealGener{0, 10, 0.5}, &rangeRealGener{0, 100, 0.5}}},
+
+	},
 }
 
 func (s *testEvaluatorSuite) TestVectorizedBuiltinMathEvalOneVec(c *C) {