statistics: add historgram bench for MergePartitionHist2GlobalHist (#…

…46788)

close #46805

statistics/BUILD.bazel

@@ -66,6 +66,7 @@ go_test(
  "cmsketch_bench_test.go",
  "cmsketch_test.go",
  "fmsketch_test.go",
+ "histogram_bench_test.go",
  "histogram_test.go",
  "integration_test.go",
  "main_test.go",

statistics/histogram_bench_test.go

@@ -0,0 +1,107 @@
+// Copyright 2023 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package statistics
+
+import (
+ "fmt"
+ "math/rand"
+ "testing"
+
+ "github.com/pingcap/tidb/parser/mysql"
+ "github.com/pingcap/tidb/types"
+ "github.com/pingcap/tidb/util/codec"
+ "github.com/pingcap/tidb/util/mock"
+ "github.com/stretchr/testify/require"
+)
+
+const (
+ histogramLen = 100
+ popedTopNLen = 100
+ expBucketNumber = 100
+)
+
+func genBucket4TestData(length int) []*bucket4Test {
+ result := make([]*bucket4Test, 0, length)
+ var lower, upper int64
+ for n := 0; n < length; n++ {
+ if n == 0 {
+ lower = 0
+ } else {
+ lower = upper + 1
+ }
+ if n == length-1 {
+ upper = 10000
+ } else {
+ upper = lower + (rand.Int63n(int64(100*(n+1)) - lower))
+ }
+ result = append(result, &bucket4Test{
+ lower: lower,
+ upper: upper,
+ count: rand.Int63n(10000),
+ repeat: rand.Int63n(100),
+ ndv: rand.Int63n(100),
+ })
+ }
+ return result
+}
+
+func genHist4Bench(t *testing.B, buckets []*bucket4Test, totColSize int64) *Histogram {
+ h := NewHistogram(0, 0, 0, 0, types.NewFieldType(mysql.TypeBlob), len(buckets), totColSize)
+ for _, bucket := range buckets {
+ lower, err := codec.EncodeKey(nil, nil, types.NewIntDatum(bucket.lower))
+ require.NoError(t, err)
+ upper, err := codec.EncodeKey(nil, nil, types.NewIntDatum(bucket.upper))
+ require.NoError(t, err)
+ di, du := types.NewBytesDatum(lower), types.NewBytesDatum(upper)
+ h.AppendBucketWithNDV(&di, &du, bucket.count, bucket.repeat, bucket.ndv)
+ }
+ return h
+}
+
+func benchmarkMergePartitionHist2GlobalHist(b *testing.B, partition int) {
+ ctx := mock.NewContext()
+ sc := ctx.GetSessionVars().StmtCtx
+ hists := make([]*Histogram, 0, partition)
+ for i := 0; i < partition; i++ {
+ buckets := genBucket4TestData(histogramLen)
+ hist := genHist4Bench(b, buckets, histogramLen)
+ hists = append(hists, hist)
+ }
+ poped := make([]TopNMeta, 0, popedTopNLen)
+ for n := 0; n < popedTopNLen; n++ {
+ b, _ := codec.EncodeKey(sc, nil, types.NewIntDatum(rand.Int63n(10000)))
+ tmp := TopNMeta{
+ Encoded: b,
+ Count: uint64(rand.Int63n(10000)),
+ }
+ poped = append(poped, tmp)
+ }
+ b.StartTimer()
+ MergePartitionHist2GlobalHist(sc, hists, poped, expBucketNumber, true)
+ b.StopTimer()
+}
+
+var benchmarkPartitionSize = []int{1000, 10000, 100000}
+
+// cmd: go test -run=^$ -bench=BenchmarkMergePartitionHist2GlobalHist -benchmem github.com/pingcap/tidb/statistics
+func BenchmarkMergePartitionHist2GlobalHist(b *testing.B) {
+ for _, size := range benchmarkPartitionSize {
+ b.Run(fmt.Sprintf("Size%d", size), func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ benchmarkMergePartitionHist2GlobalHist(b, size)
+ }
+ })
+ }
+}