Package org.apache.druid.segment.join.table

Class ReferenceCountingIndexedTable

java.lang.Object

org.apache.druid.segment.ReferenceCountingCloseableObject<IndexedTable>

org.apache.druid.segment.join.table.ReferenceCountingIndexedTable

All Implemented Interfaces:

Closeable, AutoCloseable, IndexedTable, ReferenceCountedObject

public class ReferenceCountingIndexedTable
extends ReferenceCountingCloseableObject<IndexedTable>
implements IndexedTable

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.druid.segment.join.table.IndexedTable

IndexedTable.Index, IndexedTable.Reader

Field Summary

Fields inherited from class org.apache.druid.segment.ReferenceCountingCloseableObject

baseObject, referents

Constructor Summary

Constructors

Constructor	Description
ReferenceCountingIndexedTable(IndexedTable indexedTable)

Method Summary

Modifier and Type	Method	Description
Optional<Closeable>	acquireReferences()	This method is expected to increment a reference count and provide a Closeable that decrements the reference count when closed.
IndexedTable.Index	columnIndex(int column)	Returns the index for a particular column.
IndexedTable.Reader	columnReader(int column)	Returns a reader for a particular column.
byte[]	computeCacheKey()	Computes a byte[] key for the table that can be used for computing cache keys for join operations.
boolean	isCacheable()	Returns whether this indexed table can be cached for the join operations
Set<String>	keyColumns()	Returns the columns of this table that have indexes.
int	numRows()	Returns the number of rows in this table.
RowSignature	rowSignature()	Returns the signature of this table, which includes all key columns (as well as other columns that can be selected, but are not keys).
String	version()	Returns the version of this table, used to compare against when loading a new version of the table

Methods inherited from class org.apache.druid.segment.ReferenceCountingCloseableObject

close, decrement, decrementOnceCloseable, getNumReferences, increment, incrementReferenceAndDecrementOnceCloseable, isClosed

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.io.Closeable

close

Methods inherited from interface org.apache.druid.segment.join.table.IndexedTable

makeColumnSelectorFactory

Constructor Detail

ReferenceCountingIndexedTable

public ReferenceCountingIndexedTable(IndexedTable indexedTable)

Method Detail

version

public String version()

Description copied from interface: IndexedTable

Returns the version of this table, used to compare against when loading a new version of the table

Specified by:

version in interface IndexedTable

keyColumns

public Set<String> keyColumns()

Description copied from interface: IndexedTable

Returns the columns of this table that have indexes.

Specified by:

keyColumns in interface IndexedTable

rowSignature

public RowSignature rowSignature()

Description copied from interface: IndexedTable

Returns the signature of this table, which includes all key columns (as well as other columns that can be selected, but are not keys).

Specified by:

rowSignature in interface IndexedTable

numRows

public int numRows()

Description copied from interface: IndexedTable

Returns the number of rows in this table. It must not change over time, since it is used for things like algorithm selection and reporting of cardinality metadata.

Specified by:

numRows in interface IndexedTable

columnIndex

public IndexedTable.Index columnIndex(int column)

Description copied from interface: IndexedTable

Returns the index for a particular column. The provided column number must be that column's position in IndexedTable.rowSignature().

Specified by:

columnIndex in interface IndexedTable

columnReader

public IndexedTable.Reader columnReader(int column)

Description copied from interface: IndexedTable

Returns a reader for a particular column. The provided column number must be that column's position in IndexedTable.rowSignature(). Don't forget to close your IndexedTable.Reader when finished reading, to clean up any resources.

Specified by:

columnReader in interface IndexedTable

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

computeCacheKey

public byte[] computeCacheKey()

Description copied from interface: IndexedTable

Computes a byte[] key for the table that can be used for computing cache keys for join operations. see JoinableFactory.computeJoinCacheKey(org.apache.druid.query.DataSource, org.apache.druid.segment.join.JoinConditionAnalysis)

Specified by:

computeCacheKey in interface IndexedTable

Returns:

the byte array for cache key

isCacheable

public boolean isCacheable()

Description copied from interface: IndexedTable

Returns whether this indexed table can be cached for the join operations

Specified by:

isCacheable in interface IndexedTable