diff --git a/executor.go b/executor.go index f2cb39cc0..8d29cd900 100644 --- a/executor.go +++ b/executor.go @@ -2836,34 +2836,49 @@ func newGroupByIterator(rowIDs []RowIDs, children []*pql.Call, filter *Row, inde // nextAtIdx is a recursive helper method for getting the next row for the field // at index i, and then updating the rows in the "higher" fields if it wraps. func (gbi *groupByIterator) nextAtIdx(i int) { - nr, rowID, wrapped := gbi.rowIters[i].Next() - if nr == nil { - gbi.done = true - return + // loop until we find a non-empty row. This is an optimization - the loop and if/break can be removed. + for { + nr, rowID, wrapped := gbi.rowIters[i].Next() + if nr == nil { + gbi.done = true + return + } + if wrapped && i != 0 { + gbi.nextAtIdx(i - 1) + } + if i == 0 && gbi.filter != nil { + gbi.rows[i].row = nr.Intersect(gbi.filter) + } else if i == 0 || i == len(gbi.rows)-1 { + gbi.rows[i].row = nr + } else { + gbi.rows[i].row = nr.Intersect(gbi.rows[i-1].row) + } + gbi.rows[i].id = rowID + + if !gbi.rows[i].row.IsEmpty() { + break + } } - if wrapped && i != 0 { - gbi.nextAtIdx(i - 1) - } - if i == 0 && gbi.filter != nil { - gbi.rows[i].row = nr.Intersect(gbi.filter) - } else if i == 0 || i == len(gbi.rows)-1 { - gbi.rows[i].row = nr - } else { - gbi.rows[i].row = nr.Intersect(gbi.rows[i-1].row) - } - gbi.rows[i].id = rowID } // Next returns a GroupCount representing the next group by record. When there // are no more records it will return an empty GroupCount and done==true. func (gbi *groupByIterator) Next() (ret GroupCount, done bool) { - if gbi.done { - return ret, true - } - if len(gbi.rows) == 1 { - ret.Count = gbi.rows[len(gbi.rows)-1].row.Count() - } else { - ret.Count = gbi.rows[len(gbi.rows)-1].row.intersectionCount(gbi.rows[len(gbi.rows)-2].row) + // loop until we find a result with count > 0 + for { + if gbi.done { + return ret, true + } + if len(gbi.rows) == 1 { + ret.Count = gbi.rows[len(gbi.rows)-1].row.Count() + } else { + ret.Count = gbi.rows[len(gbi.rows)-1].row.intersectionCount(gbi.rows[len(gbi.rows)-2].row) + } + if ret.Count == 0 { + gbi.nextAtIdx(len(gbi.rows) - 1) + continue + } + break } ret.Group = make([]FieldRow, len(gbi.rows)) @@ -2873,6 +2888,7 @@ func (gbi *groupByIterator) Next() (ret GroupCount, done bool) { } // set up for next call + gbi.nextAtIdx(len(gbi.rows) - 1) return ret, false diff --git a/row.go b/row.go index 9f8f9a403..255c3e847 100644 --- a/row.go +++ b/row.go @@ -42,6 +42,19 @@ func NewRow(columns ...uint64) *Row { return r } +func (r *Row) IsEmpty() bool { + if len(r.segments) == 0 { + return true + } + for i := range r.segments { + if r.segments[i].n > 0 { + return false + } + + } + return true +} + // Merge merges data from other into r. func (r *Row) Merge(other *Row) { var segments []rowSegment diff --git a/row_test.go b/row_test.go index 7f1279ceb..49559f131 100644 --- a/row_test.go +++ b/row_test.go @@ -111,3 +111,17 @@ func TestRow_Difference_Segment(t *testing.T) { t.Fatalf("Test 2 Difference Results %v != expected %v\n", res.Columns(), exp) } } + +func TestRow_IsEmpty(t *testing.T) { + r1 := pilosa.NewRow(1, ShardWidth) + r2 := pilosa.NewRow(0, 2*ShardWidth) + res := r2.Intersect(r1) + + if r1.IsEmpty() { + t.Fatal("r1 Should Not Be Empty\n") + } + if !res.IsEmpty() { + t.Fatal("Result Should Be Empty\n") + } + +}