Package org.apache.druid.segment.projections

Class AggregateProjectionSchema

java.lang.Object

org.apache.druid.segment.projections.AggregateProjectionSchema

All Implemented Interfaces:

ProjectionSchema

public class AggregateProjectionSchema
extends Object
implements ProjectionSchema

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	AggregateProjectionSchema.SchemaBuilder

Field Summary

Fields

Modifier and Type	Field	Description
static final Comparator<AggregateProjectionSchema>	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
AggregateProjectionSchema(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()
List<String>	getColumnNames()
Granularity	getEffectiveGranularity()	If ProjectionSchema.getTimeColumnName() references a column in ProjectionSchema.getVirtualColumns() which is a time_floor expression, this method translates it into a Granularity.
DimFilter	getFilter()
List<String>	getGroupingColumns()
String	getName()
List<OrderBy>	getOrdering()	Projection sort order
List<OrderBy>	getOrderingWithTimeColumnSubstitution()	Projection sort order with ProjectionSchema.getTimeColumnName() substituted with ColumnHolder.TIME_COLUMN_NAME
String	getTimeColumnName()
int	getTimeColumnPosition()	The position of the time column in the column list
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.
static AggregateProjectionSchema.SchemaBuilder	schemaBuilder(String name)
String	toString()

Methods inherited from class java.lang.Object

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

Field Details

COMPARATOR

public static final Comparator<AggregateProjectionSchema> 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

AggregateProjectionSchema

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

Method Details

schemaBuilder

public static AggregateProjectionSchema.SchemaBuilder schemaBuilder(String name)

getColumnNames

public List<String> getColumnNames()

Specified by:

getColumnNames in interface ProjectionSchema

getName

public String getName()

Specified by:

getName in interface ProjectionSchema

getTimeColumnName

@Nullable
public String getTimeColumnName()

Specified by:

getTimeColumnName in interface ProjectionSchema

getFilter

@Nullable
public DimFilter getFilter()

getVirtualColumns

public VirtualColumns getVirtualColumns()

Specified by:

getVirtualColumns in interface ProjectionSchema

getGroupingColumns

public List<String> getGroupingColumns()

getAggregators

public AggregatorFactory[] getAggregators()

getOrdering

public List<OrderBy> getOrdering()

Description copied from interface: ProjectionSchema

Projection sort order

Specified by:

getOrdering in interface ProjectionSchema

getOrderingWithTimeColumnSubstitution

public List<OrderBy> getOrderingWithTimeColumnSubstitution()

Description copied from interface: ProjectionSchema

Projection sort order with ProjectionSchema.getTimeColumnName() substituted with ColumnHolder.TIME_COLUMN_NAME

Specified by:

getOrderingWithTimeColumnSubstitution in interface ProjectionSchema

getTimeColumnPosition

public int getTimeColumnPosition()

Description copied from interface: ProjectionSchema

The position of the time column in the column list

Specified by:

getTimeColumnPosition in interface ProjectionSchema

getEffectiveGranularity

public Granularity getEffectiveGranularity()

Description copied from interface: ProjectionSchema

If ProjectionSchema.getTimeColumnName() references a column in ProjectionSchema.getVirtualColumns() which is a time_floor expression, this method translates it into a Granularity.

Specified by:

getEffectiveGranularity in interface ProjectionSchema

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. Projections.matchAggregateProjection(AggregateProjectionSchema, CursorBuildSpec, Interval, 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