Package org.apache.druid.segment

Class AggregateProjectionMetadata.Schema

java.lang.Object

org.apache.druid.segment.AggregateProjectionMetadata.Schema

Enclosing class:

AggregateProjectionMetadata

public static class AggregateProjectionMetadata.Schema
extends Object

Field Summary

Fields

Modifier and Type	Field	Description
static final Comparator<AggregateProjectionMetadata.Schema>	COMPARATOR	It is not likely the best way to find the best matching projections, but it is the one we have for now.

Constructor Summary

Constructors

Constructor	Description
Schema(String name, String timeColumnName, DimFilter filter, VirtualColumns virtualColumns, List<String> groupingColumns, AggregatorFactory[] aggregators, List<OrderBy> ordering)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
AggregatorFactory[]	getAggregators()
Granularity	getEffectiveGranularity()
DimFilter	getFilter()
List<String>	getGroupingColumns()
String	getName()
List<OrderBy>	getOrdering()
List<OrderBy>	getOrderingWithTimeColumnSubstitution()
String	getTimeColumnName()
int	getTimeColumnPosition()
VirtualColumns	getVirtualColumns()
int	hashCode()
boolean	isInvalidGrouping(String columnName)	Check if a column is either part of groupingColumns, or at least is not present in virtualColumns.
String	toString()

Methods inherited from class java.lang.Object

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

Field Details

COMPARATOR

public static final Comparator<AggregateProjectionMetadata.Schema> COMPARATOR

It is not likely the best way to find the best matching projections, but it is the one we have for now. This comparator is used to sort all the projections in a segment "best" first, where best is defined as fewest grouping columns, most virtual columns and aggregators, as an approximation of likely to have the fewest number of rows to scan.

Constructor Details

Schema

public Schema(String name,
 @Nullable
 String timeColumnName,
 @Nullable
 DimFilter filter,
 @Nullable
 VirtualColumns virtualColumns,
 @Nullable
 List<String> groupingColumns,
 @Nullable
 AggregatorFactory[] aggregators,
 List<OrderBy> ordering)

Method Details

getName

public String getName()

getTimeColumnName

@Nullable
public String getTimeColumnName()

getFilter

@Nullable
public DimFilter getFilter()

getVirtualColumns

public VirtualColumns getVirtualColumns()

getGroupingColumns

public List<String> getGroupingColumns()

getAggregators

public AggregatorFactory[] getAggregators()

getOrdering

public List<OrderBy> getOrdering()

getOrderingWithTimeColumnSubstitution

public List<OrderBy> getOrderingWithTimeColumnSubstitution()

getTimeColumnPosition

public int getTimeColumnPosition()

getEffectiveGranularity

public Granularity getEffectiveGranularity()

isInvalidGrouping

public boolean isInvalidGrouping(@Nullable
 String columnName)

Check if a column is either part of groupingColumns, or at least is not present in virtualColumns. Naively, we would just check that grouping column contains the column in question, however, we can also use a projection when a column is truly missing.

invalid reference

Projections#matchAggregateProjection(Schema, CursorBuildSpec, Projections.PhysicalColumnChecker)

returns a match builder if the column is present as either a physical column, or a virtual column, but a virtual column could also be present for an aggregator input, so we must further check that a column not in the grouping list is also not a virtual column, the implication being that it is a missing column.

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