ReadTimeoutException on ReactiveElasticsearchClient of Spring Data Elasticsearch - spring-webflux

Question

With the default ReactiveElasticsearchClient I am getting ReadTimeoutExceptions on loadtest with jmeter when trying to index a document. I´m indexing 1 document per user. 500 concurrent user. loop count 20.
Elasticsearch cluster, the application and jmeter is all run on same machine (localhost).
Any idea why I´m getting these Exceptions? Do I need to configure the underlying WebClient of ReactiveElasticsearchClient differently?
Reference StackOverflow question for broder context: Why is my Spring MVC (Tomcat NIO, RestHighLevelClient) outperforming Webflux (Netty, ReactiveElasticsearchClient) on load test?
ReactiveElasticsearchClient:
#Configuration
public class ReactiveElasticsearchConfiguration extends AbstractReactiveElasticsearchConfiguration{
#Override
#Bean
public ReactiveElasticsearchClient reactiveElasticsearchClient() {
final ClientConfiguration clientConfiguration = ClientConfiguration.builder()
.connectedTo(getHostAndPort()) //
.build();
return ReactiveRestClients.create(clientConfiguration);
}
ReadTimeoutException:
io.netty.handler.timeout.ReadTimeoutException: null
08:50:53.010 [reactor-http-nio-8] ERROR reactor.Mono.MapFuseable.1232 - | onError(org.springframework.web.reactive.function.client.WebClientRequestException: nested exception is io.netty.handler.timeout.ReadTimeoutException)
08:50:53.010 [reactor-http-nio-8] ERROR reactor.Mono.MapFuseable.1232 -
org.springframework.web.reactive.function.client.WebClientRequestException: nested exception is io.netty.handler.timeout.ReadTimeoutException
at org.springframework.web.reactive.function.client.ExchangeFunctions$DefaultExchangeFunction.lambda$wrapException$9(ExchangeFunctions.java:137)
Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:
Error has been observed at the following site(s):
|_ checkpoint ⇢ Request to POST http://localhost:9200/person_index/_doc?refresh=true&timeout=1m [DefaultWebClient]
Stack trace:
at org.springframework.web.reactive.function.client.ExchangeFunctions$DefaultExchangeFunction.lambda$wrapException$9(ExchangeFunctions.java:137)
at reactor.core.publisher.MonoErrorSupplied.subscribe(MonoErrorSupplied.java:70)
at reactor.core.publisher.Mono.subscribe(Mono.java:4046)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:103)
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221)
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221)
at reactor.core.publisher.FluxPeek$PeekSubscriber.onError(FluxPeek.java:221)
at reactor.core.publisher.MonoNext$NextSubscriber.onError(MonoNext.java:93)
at reactor.core.publisher.MonoFlatMapMany$FlatMapManyMain.onError(MonoFlatMapMany.java:204)
at reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124)
at reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.whenError(FluxRetryWhen.java:224)
at reactor.core.publisher.FluxRetryWhen$RetryWhenOtherSubscriber.onError(FluxRetryWhen.java:273)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:413)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.onNext(FluxConcatMap.java:250)
at reactor.core.publisher.EmitterProcessor.drain(EmitterProcessor.java:491)
at reactor.core.publisher.EmitterProcessor.tryEmitNext(EmitterProcessor.java:299)
at reactor.core.publisher.SinkManySerialized.tryEmitNext(SinkManySerialized.java:97)
at reactor.core.publisher.InternalManySink.emitNext(InternalManySink.java:27)
at reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.onError(FluxRetryWhen.java:189)
at reactor.core.publisher.MonoCreate$DefaultMonoSink.error(MonoCreate.java:189)
at reactor.netty.http.client.HttpClientConnect$HttpObserver.onUncaughtException(HttpClientConnect.java:359)
at reactor.netty.ReactorNetty$CompositeConnectionObserver.onUncaughtException(ReactorNetty.java:631)
at reactor.netty.resources.DefaultPooledConnectionProvider$DisposableAcquire.onUncaughtException(DefaultPooledConnectionProvider.java:213)
at reactor.netty.resources.DefaultPooledConnectionProvider$PooledConnection.onUncaughtException(DefaultPooledConnectionProvider.java:476)
at reactor.netty.channel.FluxReceive.drainReceiver(FluxReceive.java:230)
at reactor.netty.channel.FluxReceive.onInboundError(FluxReceive.java:442)
at reactor.netty.channel.ChannelOperations.onInboundError(ChannelOperations.java:467)
at reactor.netty.channel.ChannelOperationsHandler.exceptionCaught(ChannelOperationsHandler.java:127)
at io.netty.channel.AbstractChannelHandlerContext.invokeExceptionCaught(AbstractChannelHandlerContext.java:302)
at io.netty.channel.AbstractChannelHandlerContext.invokeExceptionCaught(AbstractChannelHandlerContext.java:281)
at io.netty.channel.AbstractChannelHandlerContext.fireExceptionCaught(AbstractChannelHandlerContext.java:273)
at io.netty.handler.timeout.ReadTimeoutHandler.readTimedOut(ReadTimeoutHandler.java:98)
at io.netty.handler.timeout.ReadTimeoutHandler.channelIdle(ReadTimeoutHandler.java:90)
at io.netty.handler.timeout.IdleStateHandler$ReaderIdleTimeoutTask.run(IdleStateHandler.java:504)
at io.netty.handler.timeout.IdleStateHandler$AbstractIdleTask.run(IdleStateHandler.java:476)
at io.netty.util.concurrent.PromiseTask.runTask(PromiseTask.java:98)
at io.netty.util.concurrent.ScheduledFutureTask.run(ScheduledFutureTask.java:170)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute$$$capture(AbstractEventExecutor.java:164)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(Thread.java:748)
Caused by: io.netty.handler.timeout.ReadTimeoutException: null```