org.apache.druid.segment.join

Class HashJoinSegment

java.lang.Object

org.apache.druid.segment.join.HashJoinSegment

All Implemented Interfaces:

Closeable, AutoCloseable, ReferenceCountedObject, Segment, SegmentReference

public class HashJoinSegment
extends Object
implements SegmentReference

Represents a deep, left-heavy join of a left-hand side baseSegment onto a series of right-hand side clauses. In other words, logically the operation is: join(join(join(baseSegment, clauses[0]), clauses[1]), clauses[2]) etc.

Constructor Summary

Constructors

Constructor and Description
HashJoinSegment(SegmentReference baseSegment, List<JoinableClause> clauses, JoinFilterPreAnalysis joinFilterPreAnalysis)

Method Summary

Modifier and Type	Method and Description
Optional<Closeable>	acquireReferences() This method is expected to increment a reference count and provide a Closeable that decrements the reference count when closed.
QueryableIndex	asQueryableIndex()
StorageAdapter	asStorageAdapter()
void	close()
org.joda.time.Interval	getDataInterval()
SegmentId	getId()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.druid.segment.Segment

as

Constructor Detail

HashJoinSegment

public HashJoinSegment(SegmentReference baseSegment,
                       List<JoinableClause> clauses,
                       JoinFilterPreAnalysis joinFilterPreAnalysis)

Parameters:

baseSegment - The left-hand side base segment

clauses - The right-hand side clauses. The caller is responsible for ensuring that there are no duplicate prefixes or prefixes that shadow each other across the clauses

joinFilterPreAnalysis - Pre-analysis for the query we expect to run on this segment

Method Detail

getId

public SegmentId getId()

Specified by:

getId in interface Segment

getDataInterval

public org.joda.time.Interval getDataInterval()

Specified by:

getDataInterval in interface Segment

asQueryableIndex

@Nullable
public QueryableIndex asQueryableIndex()

Specified by:

asQueryableIndex in interface Segment

asStorageAdapter

public StorageAdapter asStorageAdapter()

Specified by:

asStorageAdapter in interface Segment

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException

acquireReferences

public Optional<Closeable> acquireReferences()

Description copied from interface: ReferenceCountedObject

This method is expected to increment a reference count and provide a Closeable that decrements the reference count when closed. This is likely just a wrapper around ReferenceCountingCloseableObject.incrementReferenceAndDecrementOnceCloseable(), but may also include any other associated references which should be incremented when this method is called, and decremented/released by the closeable. IMPORTANT NOTE: to fulfill the contract of this method, implementors must return a closeable to indicate that the reference can be acquired, even if there is nothing to close. Implementors should avoid allowing this method or the Closeable it creates to throw exceptions. For callers: if this method returns non-empty, IT MUST BE CLOSED, else reference counts can potentially leak.

Specified by:

acquireReferences in interface ReferenceCountedObject