This is an automated cherry-pick of pingcap#49808

Signed-off-by: ti-chi-bot <ti-community-prow-bot@tidb.io>

pkg/statistics/BUILD.bazel

@@ -0,0 +1,108 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "statistics",
+    srcs = [
+        "analyze.go",
+        "analyze_jobs.go",
+        "builder.go",
+        "builder_ext_stats.go",
+        "cmsketch.go",
+        "cmsketch_util.go",
+        "column.go",
+        "debugtrace.go",
+        "estimate.go",
+        "fmsketch.go",
+        "histogram.go",
+        "index.go",
+        "row_sampler.go",
+        "sample.go",
+        "scalar.go",
+        "table.go",
+    ],
+    importpath = "github.com/pingcap/tidb/pkg/statistics",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//pkg/expression",
+        "//pkg/kv",
+        "//pkg/parser/ast",
+        "//pkg/parser/charset",
+        "//pkg/parser/model",
+        "//pkg/parser/mysql",
+        "//pkg/parser/terror",
+        "//pkg/planner/util/debugtrace",
+        "//pkg/sessionctx",
+        "//pkg/sessionctx/stmtctx",
+        "//pkg/sessionctx/variable",
+        "//pkg/statistics/handle/logutil",
+        "//pkg/tablecodec",
+        "//pkg/types",
+        "//pkg/util/chunk",
+        "//pkg/util/codec",
+        "//pkg/util/collate",
+        "//pkg/util/dbterror",
+        "//pkg/util/fastrand",
+        "//pkg/util/hack",
+        "//pkg/util/intest",
+        "//pkg/util/logutil",
+        "//pkg/util/memory",
+        "//pkg/util/ranger",
+        "//pkg/util/sqlexec",
+        "@com_github_dolthub_swiss//:swiss",
+        "@com_github_pingcap_errors//:errors",
+        "@com_github_pingcap_failpoint//:failpoint",
+        "@com_github_pingcap_tipb//go-tipb",
+        "@com_github_twmb_murmur3//:murmur3",
+        "@org_golang_x_exp//maps",
+        "@org_uber_go_atomic//:atomic",
+        "@org_uber_go_zap//:zap",
+    ],
+)
+
+go_test(
+    name = "statistics_test",
+    timeout = "short",
+    srcs = [
+        "bench_daily_test.go",
+        "builder_test.go",
+        "cmsketch_test.go",
+        "fmsketch_test.go",
+        "histogram_bench_test.go",
+        "histogram_test.go",
+        "integration_test.go",
+        "main_test.go",
+        "sample_test.go",
+        "scalar_test.go",
+        "statistics_test.go",
+    ],
+    data = glob(["testdata/**"]),
+    embed = [":statistics"],
+    flaky = True,
+    shard_count = 35,
+    deps = [
+        "//pkg/config",
+        "//pkg/parser/ast",
+        "//pkg/parser/model",
+        "//pkg/parser/mysql",
+        "//pkg/sessionctx",
+        "//pkg/sessionctx/stmtctx",
+        "//pkg/statistics/handle/autoanalyze",
+        "//pkg/testkit",
+        "//pkg/testkit/testdata",
+        "//pkg/testkit/testmain",
+        "//pkg/testkit/testsetup",
+        "//pkg/types",
+        "//pkg/util/benchdaily",
+        "//pkg/util/chunk",
+        "//pkg/util/codec",
+        "//pkg/util/collate",
+        "//pkg/util/memory",
+        "//pkg/util/mock",
+        "//pkg/util/ranger",
+        "//pkg/util/sqlexec",
+        "@com_github_pingcap_errors//:errors",
+        "@com_github_pingcap_failpoint//:failpoint",
+        "@com_github_stretchr_testify//require",
+        "@org_uber_go_goleak//:goleak",
+    ],
+)

statistics/builder.go

@@ -374,6 +374,7 @@ func BuildHistAndTopN(
 		if err != nil {
 			return nil, nil, errors.Trace(err)
 		}
+<<<<<<< HEAD:statistics/builder.go
 		// For debugging invalid sample data.
 		var (
 			foundTwice      bool
@@ -417,12 +418,15 @@ func BuildHistAndTopN(
 				continue
 			}
 		}
+=======
+>>>>>>> 1fb5a9ae14a (planner: a better way to round scale factor when collecting TopN stats (#49808)):pkg/statistics/builder.go
 	}
 
 	for i := 0; i < len(topNList); i++ {
 		topNList[i].Count *= uint64(sampleFactor)
 	}
 	topn := &TopN{TopN: topNList}
+	topn.Scale(sampleFactor)
 
 	if uint64(count) <= topn.TotalCount() || int(hg.NDV) <= len(topn.TopN) {
 		// TopN includes all sample data

statistics/cmsketch.go

@@ -495,6 +495,13 @@ type TopN struct {
 	TopN []TopNMeta
 }
 
+// Scale scales the TopN by the given factor.
+func (c *TopN) Scale(scaleFactor float64) {
+	for i := range c.TopN {
+		c.TopN[i].Count = uint64(float64(c.TopN[i].Count) * scaleFactor)
+	}
+}
+
 // AppendTopN appends a topn into the TopN struct.
 func (c *TopN) AppendTopN(data []byte, count uint64) {
 	if c == nil {

statistics/cmsketch_test.go

@@ -390,3 +390,23 @@ func TestMergePartTopN2GlobalTopNWithHists(t *testing.T) {
 	require.Equal(t, uint64(55), globalTopN.TotalCount(), "should have 55")
 	require.Len(t, leftTopN, 1, "should have 1 left topN")
 }
+
+func TestTopNScale(t *testing.T) {
+	for _, scaleFactor := range []float64{0.9999, 1.00001, 1.9999, 4.9999, 5.001, 9.99} {
+		var data []TopNMeta
+		sumCount := uint64(0)
+		for i := 0; i < 20; i++ {
+			cnt := uint64(rand.Intn(100000))
+			data = append(data, TopNMeta{
+				Count: cnt,
+			})
+			sumCount += cnt
+		}
+		topN := TopN{TopN: data}
+		topN.Scale(scaleFactor)
+		scaleCount := float64(sumCount) * scaleFactor
+		delta := math.Abs(float64(topN.TotalCount()) - scaleCount)
+		roundErrorRatio := delta / scaleCount
+		require.Less(t, roundErrorRatio, 0.0001)
+	}
+}