io.druid.query.groupby

Class GroupByQueryRunnerFactory

java.lang.Object

io.druid.query.groupby.GroupByQueryRunnerFactory

All Implemented Interfaces:

QueryRunnerFactory<Row,GroupByQuery>

public class GroupByQueryRunnerFactory
extends Object
implements QueryRunnerFactory<Row,GroupByQuery>

Constructor Summary

Constructors

Constructor and Description
GroupByQueryRunnerFactory(GroupByStrategySelector strategySelector, GroupByQueryQueryToolChest toolChest)

Method Summary

Modifier and Type	Method and Description
QueryRunner<Row>	createRunner(Segment segment) Given a specific segment, this method will create a QueryRunner.
QueryToolChest<Row,GroupByQuery>	getToolchest() Provides access to the toolchest for this specific query type.
QueryRunner<Row>	mergeRunners(ExecutorService exec, Iterable<QueryRunner<Row>> queryRunners) Runners generated with createRunner() and combined into an Iterable in (time,shardId) order are passed along to this method with an ExecutorService.

Methods inherited from class java.lang.Object

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

Constructor Detail

GroupByQueryRunnerFactory

@Inject
public GroupByQueryRunnerFactory(GroupByStrategySelector strategySelector,
                                         GroupByQueryQueryToolChest toolChest)

Method Detail

createRunner

public QueryRunner<Row> createRunner(Segment segment)

Description copied from interface: QueryRunnerFactory

Given a specific segment, this method will create a QueryRunner. The QueryRunner, when asked, will generate a Sequence of results based on the given segment. This is the meat of the query processing and is where the results are actually generated. Everything else is just merging and reduction logic.

Specified by:

createRunner in interface QueryRunnerFactory<Row,GroupByQuery>

Parameters:

segment - The segment to process

Returns:

A QueryRunner that, when asked, will generate a Sequence of results based on the given segment

mergeRunners

public QueryRunner<Row> mergeRunners(ExecutorService exec,
                                     Iterable<QueryRunner<Row>> queryRunners)

Description copied from interface: QueryRunnerFactory

Runners generated with createRunner() and combined into an Iterable in (time,shardId) order are passed along to this method with an ExecutorService. The method should then return a QueryRunner that, when asked, will use the ExecutorService to run the base QueryRunners in some fashion. The vast majority of the time, this should be implemented with return new ChainedExecutionQueryRunner<>( queryExecutor, toolChest.getOrdering(), queryWatcher, queryRunners ); Which will allow for parallel execution up to the maximum number of processing threads allowed.

Specified by:

mergeRunners in interface QueryRunnerFactory<Row,GroupByQuery>

Parameters:

exec - ExecutorService to be used for parallel processing

queryRunners - Individual QueryRunner objects that produce some results

Returns:

a QueryRunner that, when asked, will use the ExecutorService to run the base QueryRunners

getToolchest

public QueryToolChest<Row,GroupByQuery> getToolchest()

Description copied from interface: QueryRunnerFactory

Provides access to the toolchest for this specific query type.

Specified by:

getToolchest in interface QueryRunnerFactory<Row,GroupByQuery>

Returns:

an instance of the toolchest for this specific query type.