expression: implement vectorized evaluation for `builtinCastStringAsR…

…ealSig` (pingcap#13445)
breezewish · Nov 18, 2019 · 0b41fe9 · 0b41fe9
1 parent 66d99a1
commit 0b41fe9
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Showing 3 changed files with 58 additions and 2 deletions.
diff --git a/expression/bench_test.go b/expression/bench_test.go
@@ -406,6 +406,19 @@ func (g *numStrGener) gen() interface{} {
 	return fmt.Sprintf("%v", g.rangeInt64Gener.gen())
 }
 
+// realStrGener is used to generate real number strings.
+type realStrGener struct {
+	rangeRealGener
+}
+
+func (g *realStrGener) gen() interface{} {
+	val := g.rangeRealGener.gen()
+	if val == nil {
+		return nil
+	}
+	return fmt.Sprintf("%v", val)
+}
+
 // ipv6StrGener is used to generate ipv6 strings.
 type ipv6StrGener struct {
 }

diff --git a/expression/builtin_cast_vec.go b/expression/builtin_cast_vec.go
@@ -1240,11 +1240,47 @@ func (b *builtinCastJSONAsDecimalSig) vecEvalDecimal(input *chunk.Chunk, result
 }
 
 func (b *builtinCastStringAsRealSig) vectorized() bool {
-	return false
+	return true
 }
 
 func (b *builtinCastStringAsRealSig) vecEvalReal(input *chunk.Chunk, result *chunk.Column) error {
-	return errors.Errorf("not implemented")
+	if IsBinaryLiteral(b.args[0]) {
+		// This block is skipped by `castAsRealFunctionClass.getFunction()`
+		return b.args[0].VecEvalReal(b.ctx, input, result)
+	}
+
+	n := input.NumRows()
+	bufStrings, err := b.bufAllocator.get(types.ETString, n)
+	if err != nil {
+		return err
+	}
+	defer b.bufAllocator.put(bufStrings)
+	if err := b.args[0].VecEvalString(b.ctx, input, bufStrings); err != nil {
+		return err
+	}
+
+	result.ResizeFloat64(n, false)
+	result.MergeNulls(bufStrings)
+	f64s := result.Float64s()
+	sc := b.ctx.GetSessionVars().StmtCtx
+	for i := 0; i < n; i++ {
+		if result.IsNull(i) {
+			continue
+		}
+		val := bufStrings.GetString(i)
+		res, err := types.StrToFloat(sc, val)
+		if err != nil {
+			return err
+		}
+		if b.inUnion && mysql.HasUnsignedFlag(b.tp.Flag) && res < 0 {
+			res = 0
+		}
+		if res, err = types.ProduceFloatWithSpecifiedTp(res, b.tp, sc); err != nil {
+			return err
+		}
+		f64s[i] = res
+	}
+	return nil
 }
 
 func (b *builtinCastStringAsDecimalSig) vectorized() bool {

diff --git a/expression/builtin_cast_vec_test.go b/expression/builtin_cast_vec_test.go
@@ -20,6 +20,7 @@ import (
 
 	. "github.com/pingcap/check"
 	"github.com/pingcap/parser/ast"
+	"github.com/pingcap/parser/mysql"
 	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/types/json"
 )
@@ -38,6 +39,12 @@ var vecBuiltinCastCases = map[string][]vecExprBenchCase{
 		{retEvalType: types.ETReal, childrenTypes: []types.EvalType{types.ETJson}},
 		{retEvalType: types.ETReal, childrenTypes: []types.EvalType{types.ETDecimal}},
 		{retEvalType: types.ETReal, childrenTypes: []types.EvalType{types.ETDatetime}},
+		{retEvalType: types.ETReal, childrenTypes: []types.EvalType{types.ETString},
+			geners: []dataGenerator{&realStrGener{rangeRealGener{begin: -100000.0, end: 100000.0, nullRation: 0.5}}},
+		},
+		{retEvalType: types.ETReal, childrenTypes: []types.EvalType{types.ETString},
+			constants: []*Constant{{Value: types.NewBinaryLiteralDatum([]byte("TiDB")), RetType: types.NewFieldType(mysql.TypeVarString)}},
+		},
 		{retEvalType: types.ETDuration, childrenTypes: []types.EvalType{types.ETDatetime},
 			geners: []dataGenerator{&dateTimeGenerWithFsp{
 				defaultGener: defaultGener{nullRation: 0.2, eType: types.ETDatetime},