* new interval based cost function
Addresses issues with balancing of segments in the existing cost function
- `gapPenalty` led to clusters of segments ~30 days apart
- `recencyPenalty` caused imbalance among recent segments
- size-based cost could be skewed by compression
New cost function is purely based on segment intervals:
- assumes each time-slice of a partition is a constant cost
- cost is additive, i.e. cost(A, B union C) = cost(A, B) + cost(A, C)
- cost decays exponentially based on distance between time-slices
* comments and formatting
* add more comments to explain the calculation
BoundFilter:
- For lexicographic bounds, use bitmapIndex.getIndex to find the start and end points,
then union all bitmaps between those points.
- For alphanumeric bounds, iterate through dimValues, and union all bitmaps for values
matching the predicate.
- Change behavior for nulls: it used to be that the BoundFilter would never match nulls,
now it matches nulls if "" is allowed by the lower limit and not excluded by the
upper limit.
Interface changes:
- BitmapIndex: add `int getIndex(value)` to make it possible to get the index for a
value without retrieving the bitmap.
- BitmapIndex: remove `ImmutableBitmap getBitmap(value)`, change callers to `getBitmap(getIndex(value))`.
- BitmapIndexSelector: allow retrieving the underlying BitmapIndex through getBitmapIndex.
- Clarified contract of indexOf in Indexed, GenericIndexed.
Also added tests for SelectorFilter, NotFilter, and BoundFilter.
Charles Allen
Xavier Léauté
John Wang
Gian Merlino
jon-wei
Himanshu Gupta
Xavier Léauté
nishant