Package org.apache.druid.segment.index

Interface BitmapColumnIndex

All Known Implementing Classes:

AllFalseBitmapColumnIndex, AllTrueBitmapColumnIndex, AllUnknownBitmapColumnIndex, DictionaryRangeScanningBitmapIndex, DictionaryScanningBitmapIndex, SimpleBitmapColumnIndex, SimpleImmutableBitmapDelegatingIterableIndex, SimpleImmutableBitmapIndex, SimpleImmutableBitmapIterableIndex, ValueSetIndexes.BaseValueSetIndexesFromIterable

public interface BitmapColumnIndex

Common interface for bitmap indexes for use by Filter for cursor creation, to allow fast row skipping during query processing. Ideally implementaitons of this are 'lazy', and not do any real work until computeBitmapResult(BitmapResultFactory, int, int, boolean) or computeBitmapResult(BitmapResultFactory, boolean) is called.

Method Summary

Modifier and Type	Method	Description
<T> T	computeBitmapResult(BitmapResultFactory<T> bitmapResultFactory, boolean includeUnknown)	Compute a bitmap result wrapped with the BitmapResultFactory representing the rows matched by this index.
default <T> T	computeBitmapResult(BitmapResultFactory<T> bitmapResultFactory, int applyRowCount, int totalRowCount, boolean includeUnknown)	Compute a bitmap result wrapped with the BitmapResultFactory representing the rows matched by this index, or null if the index cannot (or should not) be computed.
int	estimatedComputeCost()	Returns an estimated cost for computing the bitmap result.
ColumnIndexCapabilities	getIndexCapabilities()

Method Details

getIndexCapabilities

ColumnIndexCapabilities getIndexCapabilities()

estimatedComputeCost

int estimatedComputeCost()

Returns an estimated cost for computing the bitmap result. Generally this is equivalent to number of bitmap union or intersection operations need to be performed. E.x. null value index bitmap has a cost of 0, non-null value index bitmap union with null bitmap has a cost of 1, range (size of 10) scanning index bitmap union with null bitmap has a cost of 10.

computeBitmapResult

<T> T computeBitmapResult(BitmapResultFactory<T> bitmapResultFactory,
 boolean includeUnknown)

Compute a bitmap result wrapped with the BitmapResultFactory representing the rows matched by this index. If building a cursor, use computeBitmapResult(BitmapResultFactory, int, int, boolean) instead.

Parameters:

bitmapResultFactory - helper to format the ImmutableBitmap in a form ready for consumption by callers

includeUnknown - mapping for Druid native two state logic system into SQL three-state logic system. If set to true, bitmaps returned by this method should include true bits for any rows where the matching result is 'unknown', such as from the input being null valued.

Returns:

bitmap result representing rows matched by this index

computeBitmapResult

@Nullable
default <T> T computeBitmapResult(BitmapResultFactory<T> bitmapResultFactory,
 int applyRowCount,
 int totalRowCount,
 boolean includeUnknown)

Compute a bitmap result wrapped with the BitmapResultFactory representing the rows matched by this index, or null if the index cannot (or should not) be computed.

Parameters:

bitmapResultFactory - helper to format the ImmutableBitmap in a form ready for consumption by callers

applyRowCount - upper bound on number of rows this filter would be applied to, after removing rows short-circuited by prior bundle operations. For example, given "x AND y", if "x" is resolved using an index, then "y" will receive the number of rows that matched the filter "x". As another example, given "x OR y", if "x" is resolved using an index, then "y" will receive the number of rows that did *not* match the filter "x".

totalRowCount - total number of rows to be scanned if no indexes are used

includeUnknown - mapping for Druid native two state logic system into SQL three-state logic system. If set to true, bitmaps returned by this method should include true bits for any rows where the matching result is 'unknown', such as from the input being null valued.

Returns:

bitmap result representing rows matched by this index