org.apache.druid.query.filter

Class FilterTuning

java.lang.Object

org.apache.druid.query.filter.FilterTuning

@SubclassesMustOverrideEqualsAndHashCode
public class FilterTuning
extends Object

This class provides a mechansim to influence whether or not indexes are used for a Filter during processing by QueryableIndexStorageAdapter.analyzeFilter(org.apache.druid.query.filter.Filter, org.apache.druid.segment.ColumnSelectorBitmapIndexSelector, org.apache.druid.query.QueryMetrics) (i.e. will a Filter be a "pre" filter in which we union indexes for all values that match the filter to create a BitmapOffset/BitmapVectorOffset, or will it be used as a "post" filter and evaluated while scanning row values from the FilteredOffset/FilteredVectorOffset. This is currently only manually supplied by the user by adding to a DimFilter which will pass through to the Filter implementation. The main purpose at this time is to facilitate experimentation so that someday we can have Filter implementations intelligently, automatically use sensible defaults based on things like cardinality and who yet knows what additional information. It can also be used for advanced users to manually control which filters will be "pre" and "post" filters as described above to allow skipping indexes in known cases where filters are expensive (mostly high cardinality columns with expensive filters). As such, it is currently undocumented in user facing documentation on purpose, but whatever this turns into once more automatic usage of this is in place, should be documented in a future release.

Constructor Summary

Constructors

Constructor and Description
FilterTuning(Boolean useBitmapIndex, Integer minCardinalityToUseBitmapIndex, Integer maxCardinalityToUseBitmapIndex)

Method Summary

Modifier and Type	Method and Description
static FilterTuning	createDefault(Filter filter, BitmapIndexSelector selector)
boolean	equals(Object o)
int	getMaxCardinalityToUseBitmapIndex()
int	getMinCardinalityToUseBitmapIndex()
boolean	getUseBitmapIndex()
int	hashCode()
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

FilterTuning

public FilterTuning(@Nullable
                    Boolean useBitmapIndex,
                    @Nullable
                    Integer minCardinalityToUseBitmapIndex,
                    @Nullable
                    Integer maxCardinalityToUseBitmapIndex)

Method Detail

createDefault

public static FilterTuning createDefault(Filter filter,
                                         BitmapIndexSelector selector)

getUseBitmapIndex

public boolean getUseBitmapIndex()

getMinCardinalityToUseBitmapIndex

public int getMinCardinalityToUseBitmapIndex()

getMaxCardinalityToUseBitmapIndex

public int getMaxCardinalityToUseBitmapIndex()

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object