Package org.apache.druid.segment.projections

Class Projections

java.lang.Object

org.apache.druid.segment.projections.Projections

public class Projections
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Projections.PhysicalColumnChecker	Returns true if column is defined in AggregateProjectionSpec.getGroupingColumns() OR if the column does not exist in the base table.

Method Summary

Modifier and Type	Method	Description
static <T> QueryableProjection<T>	findMatchingProjection(CursorBuildSpec cursorBuildSpec, SortedSet<AggregateProjectionMetadata> projections, org.joda.time.Interval dataInterval, Projections.PhysicalColumnChecker physicalChecker, Function<String,T> getRowSelector)
static String	getProjectionSmooshV9FileName(AggregateProjectionMetadata projectionSpec, String columnName)
static String	getProjectionSmooshV9Prefix(AggregateProjectionMetadata projectionSpec)
static ProjectionMatch	matchAggregateProjection(AggregateProjectionMetadata.Schema projection, CursorBuildSpec queryCursorBuildSpec, org.joda.time.Interval dataInterval, Projections.PhysicalColumnChecker physicalColumnChecker)	Check if this projection "matches" a CursorBuildSpec for a query to see if we can use a projection instead.
static ProjectionMatchBuilder	matchAggregators(AggregateProjectionMetadata.Schema projection, CursorBuildSpec queryCursorBuildSpec, Projections.PhysicalColumnChecker physicalColumnChecker, ProjectionMatchBuilder matchBuilder)
static ProjectionMatchBuilder	matchFilter(AggregateProjectionMetadata.Schema projection, CursorBuildSpec queryCursorBuildSpec, Projections.PhysicalColumnChecker physicalColumnChecker, ProjectionMatchBuilder matchBuilder)
static ProjectionMatchBuilder	matchGrouping(AggregateProjectionMetadata.Schema projection, CursorBuildSpec queryCursorBuildSpec, Projections.PhysicalColumnChecker physicalColumnChecker, ProjectionMatchBuilder matchBuilder)
static ProjectionMatchBuilder	matchQueryPhysicalColumn(String column, AggregateProjectionMetadata.Schema projection, Projections.PhysicalColumnChecker physicalColumnChecker, ProjectionMatchBuilder matchBuilder)
static ProjectionMatchBuilder	matchQueryVirtualColumn(VirtualColumn queryVirtualColumn, AggregateProjectionMetadata.Schema projection, CursorBuildSpec queryCursorBuildSpec, Projections.PhysicalColumnChecker physicalColumnChecker, ProjectionMatchBuilder matchBuilder)
static ProjectionMatchBuilder	matchQueryVirtualColumns(AggregateProjectionMetadata.Schema projection, CursorBuildSpec queryCursorBuildSpec, Projections.PhysicalColumnChecker physicalColumnChecker, ProjectionMatchBuilder matchBuilder)
static ProjectionMatchBuilder	matchRequiredColumn(String column, AggregateProjectionMetadata.Schema projection, CursorBuildSpec queryCursorBuildSpec, Projections.PhysicalColumnChecker physicalColumnChecker, ProjectionMatchBuilder matchBuilder)	Ensure that the projection has the specified column required by a CursorBuildSpec in one form or another.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

findMatchingProjection

@Nullable
public static <T> QueryableProjection<T> findMatchingProjection(CursorBuildSpec cursorBuildSpec,
 SortedSet<AggregateProjectionMetadata> projections,
 org.joda.time.Interval dataInterval,
 Projections.PhysicalColumnChecker physicalChecker,
 Function<String,T> getRowSelector)

matchAggregateProjection

@Nullable
public static ProjectionMatch matchAggregateProjection(AggregateProjectionMetadata.Schema projection,
 CursorBuildSpec queryCursorBuildSpec,
 org.joda.time.Interval dataInterval,
 Projections.PhysicalColumnChecker physicalColumnChecker)

Check if this projection "matches" a CursorBuildSpec for a query to see if we can use a projection instead. For a projection to match, all grouping columns of the build spec must match, virtual columns of the build spec must either be available as a physical column on the projection, or the inputs to the virtual column must be available on the projection, and all aggregators must be compatible with pre-aggregated columns of the projection per AggregatorFactory.substituteCombiningFactory(AggregatorFactory). If the projection matches, this method returns a ProjectionMatch which contains an updated CursorBuildSpec which has the remaining virtual columns from the original build spec which must still be computed and the 'combining' aggregator factories to process the pre-aggregated data from the projection, as well as a mapping of query column names to projection column names.

Parameters:

projection - the AggregateProjectionMetadata.Schema to check for match

queryCursorBuildSpec - the CursorBuildSpec that contains the required inputs to build a CursorHolder for a query

physicalColumnChecker - Helper utility which can determine if a physical column required by queryCursorBuildSpec is available on the projection OR does not exist on the base table either

Returns:

a ProjectionMatch if the CursorBuildSpec matches the projection, else null

matchQueryVirtualColumns

@Nullable
public static ProjectionMatchBuilder matchQueryVirtualColumns(AggregateProjectionMetadata.Schema projection,
 CursorBuildSpec queryCursorBuildSpec,
 Projections.PhysicalColumnChecker physicalColumnChecker,
 ProjectionMatchBuilder matchBuilder)

matchFilter

@Nullable
public static ProjectionMatchBuilder matchFilter(AggregateProjectionMetadata.Schema projection,
 CursorBuildSpec queryCursorBuildSpec,
 Projections.PhysicalColumnChecker physicalColumnChecker,
 ProjectionMatchBuilder matchBuilder)

matchGrouping

@Nullable
public static ProjectionMatchBuilder matchGrouping(AggregateProjectionMetadata.Schema projection,
 CursorBuildSpec queryCursorBuildSpec,
 Projections.PhysicalColumnChecker physicalColumnChecker,
 ProjectionMatchBuilder matchBuilder)

matchAggregators

@Nullable
public static ProjectionMatchBuilder matchAggregators(AggregateProjectionMetadata.Schema projection,
 CursorBuildSpec queryCursorBuildSpec,
 Projections.PhysicalColumnChecker physicalColumnChecker,
 ProjectionMatchBuilder matchBuilder)

matchRequiredColumn

@Nullable
public static ProjectionMatchBuilder matchRequiredColumn(String column,
 AggregateProjectionMetadata.Schema projection,
 CursorBuildSpec queryCursorBuildSpec,
 Projections.PhysicalColumnChecker physicalColumnChecker,
 ProjectionMatchBuilder matchBuilder)

Ensure that the projection has the specified column required by a CursorBuildSpec in one form or another. If the column is a VirtualColumn on the build spec, ensure that the projection has an equivalent virtual column, or has the required inputs to compute the virtual column. If an equivalent virtual column exists, its name will be added to ProjectionMatchBuilder.remapColumn(String, String) so the query virtual column name\ can be mapped to the projection physical column name. If no equivalent virtual column exists, but the inputs are available on the projection to compute it, it will be added to ProjectionMatchBuilder.addReferenceedVirtualColumn(VirtualColumn).

Finally, if the column is not a virtual column in the query, it is checked with Projections.PhysicalColumnChecker which true if the column is present on the projection OR if the column is NOT present on the base table (meaning missing columns that do not exist anywhere do not disqualify a projection from being used).

Parameters:

column - Column name to check

projection - AggregateProjectionMetadata.Schema to match against

queryCursorBuildSpec - the CursorBuildSpec required by the query

physicalColumnChecker - Helper to check if the physical column exists on a projection, or does not exist on the base table

matchBuilder - match state to add mappings of query virtual columns to projection physical columns and query virtual columns which still must be computed from projection physical columns

Returns:

ProjectionMatchBuilder with updated state per the rules described above, or null if the column cannot be matched

matchQueryVirtualColumn

@Nullable
public static ProjectionMatchBuilder matchQueryVirtualColumn(VirtualColumn queryVirtualColumn,
 AggregateProjectionMetadata.Schema projection,
 CursorBuildSpec queryCursorBuildSpec,
 Projections.PhysicalColumnChecker physicalColumnChecker,
 ProjectionMatchBuilder matchBuilder)

matchQueryPhysicalColumn

@Nullable
public static ProjectionMatchBuilder matchQueryPhysicalColumn(String column,
 AggregateProjectionMetadata.Schema projection,
 Projections.PhysicalColumnChecker physicalColumnChecker,
 ProjectionMatchBuilder matchBuilder)

getProjectionSmooshV9FileName

public static String getProjectionSmooshV9FileName(AggregateProjectionMetadata projectionSpec,
 String columnName)

getProjectionSmooshV9Prefix

public static String getProjectionSmooshV9Prefix(AggregateProjectionMetadata projectionSpec)