executor: fix wrong partition boundary for window functions (#11637) (#…

…11825)

executor/window.go

@@ -62,7 +62,7 @@ func (e *WindowExec) Next(ctx context.Context, chk *chunk.Chunk) error {
  defer func() { e.runtimeStats.Record(time.Now().Sub(start), chk.NumRows()) }()
  }
  chk.Reset()
- if e.meetNewGroup && e.remainingRowsInGroup > 0 {
+ if (e.executed || e.meetNewGroup) && e.remainingRowsInGroup > 0 {
  err := e.appendResult2Chunk(chk)
  if err != nil {
  return err
@@ -88,22 +88,16 @@ func (e *WindowExec) consumeOneGroup(ctx context.Context, chk *chunk.Chunk) erro
  if err != nil {
  return errors.Trace(err)
  }
- if e.meetNewGroup {
+ if e.meetNewGroup && e.remainingRowsInGroup > 0 {
  err := e.consumeGroupRows()
  if err != nil {
  return errors.Trace(err)
  }
  err = e.appendResult2Chunk(chk)
- if err != nil {
- return errors.Trace(err)
- }
+ return err
  }
  e.remainingRowsInGroup++
  e.groupRows = append(e.groupRows, e.inputRow)
- if e.meetNewGroup {
- e.inputRow = e.inputIter.Next()
- return nil
- }
  }
  return nil
 }

executor/window_test.go

@@ -172,6 +172,10 @@ func (s *testSuite4) TestWindowFunctions(c *C) {
  result.Check(testkit.Rows("1 3", "2 3", "3 6", "4 6"))
  result = tk.MustQuery("select row_number() over w, sum(b) over w from t window w as (rows between 1 preceding and 1 following)")
  result.Check(testkit.Rows("1 3", "2 4", "3 5", "4 3"))
+
+ tk.Se.GetSessionVars().MaxChunkSize = 1
+ result = tk.MustQuery("select a, row_number() over (partition by a) from t")
+ result.Check(testkit.Rows("1 1", "1 2", "2 1", "2 2"))
 }
 
 func (s *testSuite4) TestWindowFunctionsIssue11614(c *C) {

util/chunk/chunk.go

@@ -79,15 +79,15 @@ func New(fields []*types.FieldType, cap, maxChunkSize int) *Chunk {
 
 // renewWithCapacity creates a new Chunk based on an existing Chunk with capacity. The newly
 // created Chunk has the same data schema with the old Chunk.
-func renewWithCapacity(chk *Chunk, cap int) *Chunk {
+func renewWithCapacity(chk *Chunk, cap, maxChunkSize int) *Chunk {
  newChk := new(Chunk)
  if chk.columns == nil {
  return newChk
  }
  newChk.columns = renewColumns(chk.columns, cap)
  newChk.numVirtualRows = 0
  newChk.capacity = cap
- newChk.requiredRows = cap
+ newChk.requiredRows = maxChunkSize
  return newChk
 }
 
@@ -98,7 +98,7 @@ func renewWithCapacity(chk *Chunk, cap int) *Chunk {
 // maxChunkSize: the limit for the max number of rows.
 func Renew(chk *Chunk, maxChunkSize int) *Chunk {
  newCap := reCalcCapacity(chk, maxChunkSize)
- return renewWithCapacity(chk, newCap)
+ return renewWithCapacity(chk, newCap, maxChunkSize)
 }
 
 // renewColumns creates the columns of a Chunk. The capacity of the newly

util/chunk/row.go

@@ -225,7 +225,7 @@ func (r Row) IsNull(colIdx int) bool {
 
 // CopyConstruct creates a new row and copies this row's data into it.
 func (r Row) CopyConstruct() Row {
- newChk := renewWithCapacity(r.c, 1)
+ newChk := renewWithCapacity(r.c, 1, 1)
  newChk.AppendRow(r)
  return newChk.GetRow(0)
 }