org.apache.druid.query

Interface QueryProcessingPool

All Superinterfaces:

Executor, ExecutorService, com.google.common.util.concurrent.ListeningExecutorService

All Known Implementing Classes:

DirectQueryProcessingPool, ForwardingQueryProcessingPool, MetricsEmittingQueryProcessingPool

public interface QueryProcessingPool
extends com.google.common.util.concurrent.ListeningExecutorService

This class implements the logic of how units of query execution run concurrently. It is used in QueryRunnerFactory.mergeRunners(QueryProcessingPool, Iterable). In a most straightforward implementation, each unit will be submitted to an PrioritizedExecutorService. Extensions, however, can implement their own logic for picking which unit to pick first for execution.

This interface extends ListeningExecutorService as well. It has a separate method to submit query execution tasks so that implementations can differentiate those tasks from any regular async tasks. One example is GroupByStrategyV2.mergeRunners(QueryProcessingPool, Iterable) where different kind of tasks are submitted to same processing pool.

Query execution task also includes a reference to QueryRunner so that any state required to decide the priority of a unit can be carried forward with the corresponding QueryRunner.

Method Summary

Modifier and Type	Method and Description
<T,V> com.google.common.util.concurrent.ListenableFuture<T>	submitRunnerTask(PrioritizedQueryRunnerCallable<T,V> task) Submits the query execution unit task for asynchronous execution.

Methods inherited from interface com.google.common.util.concurrent.ListeningExecutorService

invokeAll, invokeAll, submit, submit, submit

Methods inherited from interface java.util.concurrent.ExecutorService

awaitTermination, invokeAny, invokeAny, isShutdown, isTerminated, shutdown, shutdownNow

Methods inherited from interface java.util.concurrent.Executor

execute

Method Detail

submitRunnerTask

<T,V> com.google.common.util.concurrent.ListenableFuture<T> submitRunnerTask(PrioritizedQueryRunnerCallable<T,V> task)

Submits the query execution unit task for asynchronous execution.

Type Parameters:

T - - Task result type

V - - Query runner sequence type

Parameters:

task - - Task to be submitted.

Returns:

- Future object for tracking the task completion.