ArrayIndexOutOfBoundsException in a connection to Redis

[milen-georgiev-axway]

Hi there,

We use Sprint WebFlux with Lettuce for Redis connections. We 've had an incident with a frozen Lettuce thread, because of
java.lang.ArrayIndexOutOfBoundsException at at org.davidmoten.rx.pool.MemberSingle.tryEmit(MemberSingle.java:276)

Please advise.

Here is the stacktrace:

stack_trace
java.lang.NullPointerException: subscribeActual failed
at io.reactivex.Single.subscribe(Single.java:3671)
at io.reactivex.internal.operators.single.SingleMap.subscribeActual(SingleMap.java:34)
at io.reactivex.Single.subscribe(Single.java:3666)
at io.reactivex.internal.operators.single.SingleToFlowable.subscribeActual(SingleToFlowable.java:37)
at io.reactivex.Flowable.subscribe(Flowable.java:14935)
at io.reactivex.internal.operators.flowable.FlowableFlatMap.subscribeActual(FlowableFlatMap.java:53)
at io.reactivex.Flowable.subscribe(Flowable.java:14935)
at io.reactivex.Flowable.subscribe(Flowable.java:14885)
at reactor.core.publisher.MonoFromPublisher.subscribe(MonoFromPublisher.java:63)
at reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64)
at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:157)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.MonoMetrics$MetricsSubscriber.onNext(MonoMetrics.java:127)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.FluxUsingWhen$UsingWhenSubscriber.onNext(FluxUsingWhen.java:358)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:120)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.MonoFlatMapMany$FlatMapManyInner.onNext(MonoFlatMapMany.java:250)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.innerNext(FluxConcatMap.java:281)
at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:860)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:73)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:120)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:120)
at com.axway.salesforcePanelService.utils.MDCSubscriberWrapper.onNext(MDCUtils.kt:75)
at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82)
at reactor.core.publisher.MonoNext$NextSubscriber.onNext(MonoNext.java:82)
at io.lettuce.core.RedisPublisher$ImmediateSubscriber.onNext(RedisPublisher.java:886)
at io.lettuce.core.RedisPublisher$RedisSubscription.onNext(RedisPublisher.java:291)
at io.lettuce.core.RedisPublisher$SubscriptionCommand.doOnComplete(RedisPublisher.java:773)
at io.lettuce.core.protocol.CommandWrapper.complete(CommandWrapper.java:65)
at io.lettuce.core.protocol.CommandWrapper.complete(CommandWrapper.java:63)
at io.lettuce.core.protocol.CommandHandler.complete(CommandHandler.java:742)
at io.lettuce.core.protocol.CommandHandler.decode(CommandHandler.java:677)
at io.lettuce.core.protocol.CommandHandler.channelRead(CommandHandler.java:594)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:719)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:655)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:581)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493)
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: java.lang.ArrayIndexOutOfBoundsException: 0
at org.davidmoten.rx.pool.MemberSingle.tryEmit(MemberSingle.java:276)
at org.davidmoten.rx.pool.MemberSingle.drain(MemberSingle.java:190)
at org.davidmoten.rx.pool.MemberSingle.subscribeActual(MemberSingle.java:113)
at io.reactivex.Single.subscribe(Single.java:3666)
... 60 common frames omitted

thread_name
lettuce-nioEventLoop-7-1

==============================

This is part of build.gradle

plugins {
id("org.springframework.boot") version "2.4.7"
id("io.spring.dependency-management") version "1.0.11.RELEASE"
id("com.gorylenko.gradle-git-properties") version "2.2.4"

kotlin("jvm") version "1.4.30"
kotlin("plugin.spring") version "1.4.30"

}

ext["snakeyaml.version"] = "1.28"
ext["netty.version"] = "4.1.63.Final"

allprojects {
repositories {
mavenCentral()
jcenter()
}

dependencyManagement {
    dependencies {
        dependency("commons-io:commons-io:2.7")
    }
}

}

dependencies {
implementation("org.springframework.boot:spring-boot-starter-data-redis-reactive")
implementation("org.springframework.boot:spring-boot-starter-webflux")
implementation("org.springframework.boot:spring-boot-starter-actuator")
implementation("io.micrometer:micrometer-registry-jmx")
implementation("com.fasterxml.jackson.module:jackson-module-kotlin")
implementation("io.projectreactor.kotlin:reactor-kotlin-extensions")
implementation("org.jetbrains.kotlin:kotlin-reflect")
implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")

implementation("org.apache.commons:commons-text:1.8")

implementation("org.apache.commons:commons-lang3")
implementation("commons-codec:commons-codec")
implementation("commons-cli:commons-cli:1.4")

implementation("net.logstash.logback:logstash-logback-encoder:5.0")

implementation("com.github.davidmoten:rxjava2-jdbc:0.2.7")
implementation("org.postgresql:postgresql:42.2.19")

testImplementation("org.springframework.boot:spring-boot-starter-test")
testImplementation("io.projectreactor:reactor-test")
testImplementation("it.ozimov:embedded-redis:0.7.1")
testImplementation("org.assertj:assertj-core:3.18.1")

}

[davidmoten]

Thanks for the report @milen-georgiev-axway. Can you review the fix #59 please? Once it has the tick I'll build a new release.

[davidmoten]

Thanks for reviewing. I didn't wait for an Approved tick from you as that was the only question. You are welcome to make more comments on the PR if you have any of course.

I've released 0.2.9 to Maven Central with the fix for this issue (actually 0.2.8 has that) and also includes an upgrade to latest rxjava2.

[milen-georgiev-axway]

Thank you very much Dave, for your quick reaction!
Just wondering, when can we expect the new version artifact to be available on Maven?

[davidmoten]

0.2.9 is already there. Not visible if you search but download works. It's usually available for download 10mins after I release and then the index for search happens within 24 hours or so.