Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

stats: fix estimation for out of range point queries (#8015) #8493

Merged
merged 3 commits into from
Nov 28, 2018
Merged

stats: fix estimation for out of range point queries (#8015) #8493

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
dc718ca
stats: fix estimation for out of range point queries (#8015)
alivxxx Oct 24, 2018
d32b7d0
Merge branch 'release-2.0' into estimation
zz-jason Nov 28, 2018
54a9a3e
Merge branch 'release-2.0' into estimation
zz-jason Nov 28, 2018
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 4 additions & 4 deletions plan/cbo_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -607,16 +607,16 @@ func (s *testAnalyzeSuite) TestLimit(c *C) {
}
testKit.MustExec("analyze table t")
testKit.MustQuery("explain select * from t use index(idx) where a > 1 and b > 1 and c > 1 limit 1").Check(testkit.Rows(
"IndexScan_13 Selection_15 cop table:t, index:a, b, range:(1 +inf,+inf +inf], keep order:false 1.10",
"Selection_15 IndexScan_13 cop gt(test.t.b, 1) 1.00",
"TableScan_14 Selection_16 cop table:t, keep order:false 1.00",
"IndexScan_13 Selection_15 cop table:t, index:a, b, range:(1 +inf,+inf +inf], keep order:false 1.56",
"Selection_15 IndexScan_13 cop gt(test.t.b, 1) 1.25",
"TableScan_14 Selection_16 cop table:t, keep order:false 1.25",
"Selection_16 Limit_17 TableScan_14 cop gt(test.t.c, 1) 1.00",
"Limit_17 Selection_16 cop offset:0, count:1 1.00",
"IndexLookUp_18 Limit_9 root index:Selection_15, table:Limit_17 1.00",
"Limit_9 IndexLookUp_18 root offset:0, count:1 1.00",
))
testKit.MustQuery("explain select * from t where a > 1 and c > 1 limit 1").Check(testkit.Rows(
"TableScan_11 Selection_12 cop table:t, range:(1,+inf], keep order:false 1.11",
"TableScan_11 Selection_12 cop table:t, range:(1,+inf], keep order:false 1.25",
"Selection_12 Limit_15 TableScan_11 cop gt(test.t.c, 1) 1.00",
"Limit_15 Selection_12 cop offset:0, count:1 1.00",
"TableReader_16 Limit_8 root data:Limit_15 1.00",
Expand Down
2 changes: 1 addition & 1 deletion statistics/ddl_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -126,7 +126,7 @@ func (s *testStatsCacheSuite) TestDDLHistogram(c *C) {
c.Assert(count, Equals, float64(2))
count, err = statsTbl.ColumnEqualRowCount(sc, types.NewIntDatum(1), tableInfo.Columns[3].ID)
c.Assert(err, IsNil)
c.Assert(count, Equals, float64(2))
c.Assert(count, Equals, float64(0))

testKit.MustExec("alter table t add column c4 datetime NOT NULL default CURRENT_TIMESTAMP")
err = h.HandleDDLEvent(<-h.DDLEventCh())
Expand Down
16 changes: 8 additions & 8 deletions statistics/histogram.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -637,7 +637,7 @@ func (c *Column) String() string {
return c.Histogram.ToString(0)
}

func (c *Column) equalRowCount(sc *stmtctx.StatementContext, val types.Datum) (float64, error) {
func (c *Column) equalRowCount(sc *stmtctx.StatementContext, val types.Datum, modifyCount int64) (float64, error) {
if val.IsNull() {
return float64(c.NullCount), nil
}
Expand All @@ -646,7 +646,7 @@ func (c *Column) equalRowCount(sc *stmtctx.StatementContext, val types.Datum) (f
return 0.0, nil
}
if c.NDV > 0 && c.outOfRange(val) {
return c.totalRowCount() / (float64(c.NDV)), nil
return float64(modifyCount) / float64(c.NDV), nil
}
if c.CMSketch != nil {
count, err := c.CMSketch.queryValue(sc, val)
Expand All @@ -667,7 +667,7 @@ func (c *Column) getColumnRowCount(sc *stmtctx.StatementContext, ranges []*range
// the point case.
if !rg.LowExclude && !rg.HighExclude {
var cnt float64
cnt, err = c.equalRowCount(sc, rg.LowVal[0])
cnt, err = c.equalRowCount(sc, rg.LowVal[0], modifyCount)
if err != nil {
return 0, errors.Trace(err)
}
Expand All @@ -681,14 +681,14 @@ func (c *Column) getColumnRowCount(sc *stmtctx.StatementContext, ranges []*range
cnt += float64(modifyCount) / outOfRangeBetweenRate
}
if rg.LowExclude {
lowCnt, err := c.equalRowCount(sc, rg.LowVal[0])
lowCnt, err := c.equalRowCount(sc, rg.LowVal[0], modifyCount)
if err != nil {
return 0, errors.Trace(err)
}
cnt -= lowCnt
}
if !rg.HighExclude {
highCnt, err := c.equalRowCount(sc, rg.HighVal[0])
highCnt, err := c.equalRowCount(sc, rg.HighVal[0], modifyCount)
if err != nil {
return 0, errors.Trace(err)
}
Expand All @@ -715,10 +715,10 @@ func (idx *Index) String() string {
return idx.Histogram.ToString(len(idx.Info.Columns))
}

func (idx *Index) equalRowCount(sc *stmtctx.StatementContext, b []byte) float64 {
func (idx *Index) equalRowCount(sc *stmtctx.StatementContext, b []byte, modifyCount int64) float64 {
val := types.NewBytesDatum(b)
if idx.NDV > 0 && idx.outOfRange(val) {
return idx.totalRowCount() / (float64(idx.NDV))
return float64(modifyCount) / (float64(idx.NDV))
}
if idx.CMSketch != nil {
return float64(idx.CMSketch.queryBytes(b))
Expand All @@ -740,7 +740,7 @@ func (idx *Index) getRowCount(sc *stmtctx.StatementContext, indexRanges []*range
fullLen := len(indexRange.LowVal) == len(indexRange.HighVal) && len(indexRange.LowVal) == len(idx.Info.Columns)
if fullLen && bytes.Equal(lb, rb) {
if !indexRange.LowExclude && !indexRange.HighExclude {
totalCount += idx.equalRowCount(sc, lb)
totalCount += idx.equalRowCount(sc, lb, modifyCount)
}
continue
}
Expand Down
22 changes: 20 additions & 2 deletions statistics/selectivity_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -154,7 +154,7 @@ func (s *testSelectivitySuite) TestSelectivity(c *C) {
},
{
exprs: "a >= 1 and b > 1 and a < 2",
selectivity: 0.01817558299,
selectivity: 0.01783264746,
},
{
exprs: "a >= 1 and c > 1 and a < 2",
Expand All @@ -170,7 +170,7 @@ func (s *testSelectivitySuite) TestSelectivity(c *C) {
},
{
exprs: "b > 1",
selectivity: 0.98148148148,
selectivity: 0.96296296296,
},
{
exprs: "a > 1 and b < 2 and c > 3 and d < 4 and e > 5",
Expand Down Expand Up @@ -279,6 +279,24 @@ func (s *testSelectivitySuite) TestEstimationForUnknownValues(c *C) {
count, err = statsTbl.GetRowCountByColumnRanges(sc, colID, getRange(1, 30))
c.Assert(err, IsNil)
c.Assert(count, Equals, 0.0)

testKit.MustExec("drop table t")
testKit.MustExec("create table t(a int, b int, index idx(b))")
testKit.MustExec("insert into t values (1,1)")
testKit.MustExec("analyze table t")
table, err = s.dom.InfoSchema().TableByName(model.NewCIStr("test"), model.NewCIStr("t"))
c.Assert(err, IsNil)
statsTbl = h.GetTableStats(table.Meta())

colID = table.Meta().Columns[0].ID
count, err = statsTbl.GetRowCountByColumnRanges(sc, colID, getRange(2, 2))
c.Assert(err, IsNil)
c.Assert(count, Equals, 0.0)

idxID = table.Meta().Indices[0].ID
count, err = statsTbl.GetRowCountByIndexRanges(sc, idxID, getRange(2, 2))
c.Assert(err, IsNil)
c.Assert(count, Equals, 0.0)
}

func (s *testSelectivitySuite) TestPrimaryKeySelectivity(c *C) {
Expand Down
2 changes: 1 addition & 1 deletion statistics/table.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -314,7 +314,7 @@ func (t *Table) ColumnEqualRowCount(sc *stmtctx.StatementContext, value types.Da
return float64(t.Count) / pseudoEqualRate, nil
}
hist := t.Columns[colID]
result, err := hist.equalRowCount(sc, value)
result, err := hist.equalRowCount(sc, value, t.ModifyCount)
result *= hist.getIncreaseFactor(t.Count)
return result, errors.Trace(err)
}
Expand Down