address comments

distsql/request_builder.go

@@ -269,7 +269,7 @@ func IndexRangesToKVRanges(sc *stmtctx.StatementContext, tid, idxID int64, range
 		feedbackRanges = append(feedbackRanges, &ranger.Range{LowVal: []types.Datum{types.NewBytesDatum(low)},
 			HighVal: []types.Datum{types.NewBytesDatum(high)}, LowExclude: false, HighExclude: true})
 	}
-	feedbackRanges = fb.Hist().SplitRange(feedbackRanges)
+	feedbackRanges = fb.Hist().SplitRange(sc, feedbackRanges)
 	krs := make([]kv.KeyRange, 0, len(feedbackRanges))
 	for _, ran := range feedbackRanges {
 		low, high := ran.LowVal[0].GetBytes(), ran.HighVal[0].GetBytes()

executor/table_reader.go

@@ -96,8 +96,9 @@ func (e *TableReaderExecutor) Open(ctx context.Context) error {
 	}
 
 	e.resultHandler = &tableResultHandler{}
+	// Split ranges here since the unsigned part and signed part will swap their position when encoding the range to kv ranges.
 	if e.feedback != nil && e.feedback.Hist() != nil {
-		e.ranges = e.feedback.Hist().SplitRange(e.ranges)
+		e.ranges = e.feedback.Hist().SplitRange(e.ctx.GetSessionVars().StmtCtx, e.ranges)
 	}
 	firstPartRanges, secondPartRanges := splitRanges(e.ranges, e.keepOrder, e.desc)
 	firstResult, err := e.buildResp(ctx, firstPartRanges)

statistics/histogram.go

@@ -503,7 +503,7 @@ func (hg *Histogram) getIncreaseFactor(totalCount int64) float64 {
 
 // validRange checks if the range is valid, it is used by `SplitRange` to remove the invalid range,
 // the possible types of range are index key range and handle key range.
-func validRange(ran *ranger.Range) bool {
+func validRange(sc *stmtctx.StatementContext, ran *ranger.Range) bool {
 	var low, high []byte
 	if ran.LowVal[0].Kind() == types.KindBytes {
 		low, high = ran.LowVal[0].GetBytes(), ran.HighVal[0].GetBytes()
@@ -530,7 +530,7 @@ func validRange(ran *ranger.Range) bool {
 // SplitRange splits the range according to the histogram upper bound. Note that we treat last bucket's upper bound
 // as inf, so all the split ranges will totally fall in one of the (-inf, u(0)], (u(0), u(1)],...(u(n-3), u(n-2)],
 // (u(n-2), +inf), where n is the number of buckets, u(i) is the i-th bucket's upper bound.
-func (hg *Histogram) SplitRange(ranges []*ranger.Range) []*ranger.Range {
+func (hg *Histogram) SplitRange(sc *stmtctx.StatementContext, ranges []*ranger.Range) []*ranger.Range {
 	split := make([]*ranger.Range, 0, len(ranges))
 	for len(ranges) > 0 {
 		// Find the last bound that greater or equal to the LowVal.
@@ -574,7 +574,7 @@ func (hg *Histogram) SplitRange(ranges []*ranger.Range) []*ranger.Range {
 				HighExclude: false})
 			ranges[0].LowVal[0] = upper
 			ranges[0].LowExclude = true
-			if !validRange(ranges[0]) {
+			if !validRange(sc, ranges[0]) {
 				ranges = ranges[1:]
 			}
 		}

statistics/update_test.go

@@ -604,7 +604,7 @@ func (s *testStatsUpdateSuite) TestSplitRange(c *C) {
 				HighExclude: t.exclude[i+1],
 			})
 		}
-		ranges = h.SplitRange(ranges)
+		ranges = h.SplitRange(nil, ranges)
 		var ranStrs []string
 		for _, ran := range ranges {
 			ranStrs = append(ranStrs, ran.String())
@@ -1344,7 +1344,7 @@ func (s *testStatsUpdateSuite) TestUnsignedFeedbackRanges(c *C) {
 	statistics.FeedbackProbability = 1
 
 	testKit.MustExec("use test")
-	testKit.MustExec("create table t (a tinyint unsigned, primary key(a))")
+	testKit.MustExec("create table t (a bigint unsigned, primary key(a))")
 	for i := 0; i < 20; i++ {
 		testKit.MustExec(fmt.Sprintf("insert into t values (%d)", i))
 	}
@@ -1371,7 +1371,7 @@ func (s *testStatsUpdateSuite) TestUnsignedFeedbackRanges(c *C) {
 			hist: "column:1 ndv:30 totColSize:0\n" +
 				"num: 8 lower_bound: 0 upper_bound: 7 repeats: 0\n" +
 				"num: 8 lower_bound: 8 upper_bound: 15 repeats: 0\n" +
-				"num: 14 lower_bound: 16 upper_bound: 255 repeats: 0",
+				"num: 14 lower_bound: 16 upper_bound: 18446744073709551615 repeats: 0",
 		},
 	}
 	is := s.do.InfoSchema()