org.apache.druid.segment

Class DeprecatedQueryableIndexColumnSelector

java.lang.Object

org.apache.druid.segment.DeprecatedQueryableIndexColumnSelector

All Implemented Interfaces:

Expr.InputBindingInspector, ColumnInspector, ColumnSelector

Deprecated.

@Deprecated
public class DeprecatedQueryableIndexColumnSelector
extends Object
implements ColumnSelector

It likely looks weird that we are creating a new instance of ColumnSelector here that begins its life deprecated and only delegates methods to the Queryable Index. This is done intentionally so that the QueryableIndex doesn't accidentally get used as a ColumnSelector. The lifecycle of the QueryableIndex is over the lifetime of the segment on a specific process, while the ColumnSelector's lifecycle is for a given query. When we don't use the same ColumnSelector for an entire query, we defeat caching and use a lot more resources than necessary for queries. Places that use this class are intentionally circumventing column caching and column lifecycle management, ostensibly because those code locations know that they are only looking at metadata. If a code path uses this and actually accesses a column instead of just looking at metadata, it will leak any resources that said column requires. The ColumnCache is the preferred implementation of a ColumnSelector, it takes a Closer and that closer can be used to ensure that resources are cleaned up.

Constructor Summary

Constructors

Constructor and Description
DeprecatedQueryableIndexColumnSelector(QueryableIndex index) Deprecated.

Method Summary

Modifier and Type	Method and Description
ColumnHolder	getColumnHolder(String columnName) Deprecated.
List<String>	getColumnNames() Deprecated. This method is apparently no longer used anymore, so deprecating it.

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.ColumnSelector

getColumnCapabilities

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

getColumnCapabilitiesWithDefault, getType

Methods inherited from interface org.apache.druid.math.expr.Expr.InputBindingInspector

areNumeric, areNumeric, areSameTypes, areSameTypes, areScalar, areScalar, canVectorize, canVectorize

Constructor Detail

DeprecatedQueryableIndexColumnSelector

public DeprecatedQueryableIndexColumnSelector(QueryableIndex index)

Deprecated.

Method Detail

getColumnNames

public List<String> getColumnNames()

Deprecated.

Description copied from interface: ColumnSelector

This method is apparently no longer used anymore, so deprecating it.

Specified by:

getColumnNames in interface ColumnSelector

getColumnHolder

@Nullable
public ColumnHolder getColumnHolder(String columnName)

Deprecated.

Specified by:

getColumnHolder in interface ColumnSelector