LTRThreadModule (Solr 7.7.0 API)

java.lang.Object
- org.apache.solr.core.CloseHook
- - org.apache.solr.ltr.LTRThreadModule

All Implemented Interfaces:

NamedListInitializedPlugin
```
public final class LTRThreadModule
extends CloseHook
implements NamedListInitializedPlugin
```
The LTRThreadModule is optionally used by the LTRQParserPlugin and LTRFeatureLoggerTransformerFactory classes to parallelize the creation of Feature.FeatureWeight objects.
Example configuration:
```
  <queryParser name="ltr" class="org.apache.solr.ltr.search.LTRQParserPlugin">
     <int name="threadModule.totalPoolThreads">10</int>
     <int name="threadModule.numThreadsPerRequest">5</int>
  </queryParser>

  <transformer name="features" class="org.apache.solr.ltr.response.transform.LTRFeatureLoggerTransformerFactory">
     <int name="threadModule.totalPoolThreads">10</int>
     <int name="threadModule.numThreadsPerRequest">5</int>
  </transformer>
```
If an individual solr instance is expected to receive no more than one query at a time, it is best to set totalPoolThreads and numThreadsPerRequest to the same value. If multiple queries need to be serviced simultaneously then totalPoolThreads and numThreadsPerRequest can be adjusted based on the expected response times. If the value of numThreadsPerRequest is higher, the response time for a single query will be improved up to a point. If multiple queries are serviced simultaneously, the value of totalPoolThreads imposes a contention between the queries if (totalPoolThreads < numThreadsPerRequest * total parallel queries).

Constructor Summary

Constructors
Constructor Description

LTRThreadModule()

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`acquireLTRSemaphore()`
`Semaphore`	`createQuerySemaphore()`
`void`	`execute(Runnable command)`
`static LTRThreadModule`	`getInstance(NamedList args)`
`void`	`init(NamedList args)`
`void`	`postClose(SolrCore core)`
`void`	`preClose(SolrCore core)`
`void`	`releaseLTRSemaphore()`
`void`	`setExecutor(ExecutorService sharedExecutor)`
`void`	`setNumThreadsPerRequest(int numThreadsPerRequest)`
`void`	`setTotalPoolThreads(int totalPoolThreads)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail
- LTRThreadModule
```
public LTRThreadModule()
```

Method Detail

getInstance

public static LTRThreadModule getInstance(NamedList args)

init
```
public void init(NamedList args)
```
Specified by:

init in interface NamedListInitializedPlugin

setTotalPoolThreads

public void setTotalPoolThreads(int totalPoolThreads)

setNumThreadsPerRequest

public void setNumThreadsPerRequest(int numThreadsPerRequest)

createQuerySemaphore

public Semaphore createQuerySemaphore()

acquireLTRSemaphore

public void acquireLTRSemaphore()
                         throws InterruptedException

Throws:: InterruptedException

releaseLTRSemaphore

public void releaseLTRSemaphore()
                         throws InterruptedException

Throws:: InterruptedException

execute

public void execute(Runnable command)

preClose
```
public void preClose(SolrCore core)
```
Specified by:

preClose in class CloseHook

postClose
```
public void postClose(SolrCore core)
```
Specified by:

postClose in class CloseHook

setExecutor

public void setExecutor(ExecutorService sharedExecutor)