PersistenceException: Multiple concurrent threads attempted to access a single broker. By default brokers are not thread safe; if you require and/or intend a broker to be accessed by more than one thread, set the openjpa.Multithreaded property to true to override the default behavior.
That is the answer to your issue. Your broker is single-threaded. You need to set the multithreaded property to handle multiple threads. Honestly, with the number of multithreaded applications out there, I am surprised that single-threaded is still a default in so many things. On Sun, Jun 4, 2023 at 11:05 PM Benoit TELLIER <btell...@apache.org> wrote: > Hello Wojtek, > > Sorry, this goes beyond my JPA skills, this would be hard for me to > support you on this issue. > > I also think that this email lacks a bit of context. > > -> Why do you try setting up connection pooling? Because of suspicions > of James continuously opening new connections? CF > https://github.com/apache/james-project/pull/1579#issuecomment-1574414163 > ? > -> Just in doubt always mention the version you are using (3.8.0? A > given pull request?) > > For instance https://github.com/apache/james-project/pull/1579 requires > to allow JPA in a multithread enviroment by setting > -Dopenjpa.Multithreaded=true (required for the inter-operability with > reactor...) cf > > https://github.com/chibenwa/james-project/blob/46168bb2f74d9186f10c101a7b6df3f5468927a5/server/apps/jpa-app/sample-configuration/jvm.properties#L53 > > > Also, if in doubt we could reach to the openjpa community... > > Best regards, > > Benoit TELLIER > > On 03/06/2023 09:01, Wojtek wrote: > > I'm trying to configure/use connection pool with OpenJPA and DBCP. > > When adding commons-dbcp:1.4 to the classpath I get error: > > > "org.apache.openjpa.persistence.PersistenceException/SQLException/com.mysql.cj.exceptions.StatementIsClosedException: > > > No operations allowed after statement closed." and no pool, > > coonections being re-created constantly and higher memory usage. > > > > With commons-dbcp2:2.9.0 I do get constant connection pool (lsof, same > > ports after a couple of tries) but James floods logs with exceptions > > about multithreading operation (below) and imapsync dies shortly due > > to erroring out. > > > > > > Is connection pooling supported? How to correctly configure it? > > > > > > OpenJPA configuration > > ( > https://openjpa.apache.org/builds/3.2.2/apache-openjpa/docs/manual.html#openjpa.jdbc.DriverDataSource) > > > seems to indicate, that DBCP2 should be available in the classpath, > > which seems to be picked up corrently and create the pool, but there > > seem to be issue with James utilizing it? > > > > ---- > > > > StackTraces/logs > > > > > > 1:55:39.878 [WARN ] i.n.c.DefaultChannelPipeline - An > > exceptionCaught() event was fired, and it reached at the tail of the > > pipeline. It usually means the last handler in the pipeline did not > > handle the exception. > > org.apache.openjpa.persistence.PersistenceException: Multiple > > concurrent threads attempted to access a single broker. By default > > brokers are not thread safe; if you require and/or intend a broker to > > be accessed by more than one thread, set the openjpa.Multithreaded > > property to true to override the default behavior. > > at > > org.apache.openjpa.kernel.BrokerImpl.endOperation(BrokerImpl.java:2083) > > at > > org.apache.openjpa.kernel.BrokerImpl.isActive(BrokerImpl.java:2028) > > at > > > org.apache.openjpa.kernel.DelegatingBroker.isActive(DelegatingBroker.java:521) > > at > > > org.apache.openjpa.persistence.EntityManagerImpl.isActive(EntityManagerImpl.java:812) > > at > > > org.apache.openjpa.persistence.PersistenceExceptions$2.translate(PersistenceExceptions.java:82) > > at > > > org.apache.openjpa.kernel.DelegatingBroker.translate(DelegatingBroker.java:108) > > at > > > org.apache.openjpa.kernel.DelegatingBroker.isActive(DelegatingBroker.java:523) > > at > > > org.apache.openjpa.persistence.EntityManagerImpl.isActive(EntityManagerImpl.java:812) > > at > > > org.apache.james.backends.jpa.EntityManagerUtils.safelyClose(EntityManagerUtils.java:37) > > at > > > org.apache.james.mailbox.jpa.JPATransactionalMapper.endRequest(JPATransactionalMapper.java:91) > > at > > > org.apache.james.mailbox.store.MailboxSessionMapperFactory.endProcessingRequest(MailboxSessionMapperFactory.java:143) > > at > > > org.apache.james.mailbox.store.StoreMailboxManager.endProcessingRequest(StoreMailboxManager.java:915) > > at > > > org.apache.james.mailbox.MailboxManager.lambda$manageProcessing$10(MailboxManager.java:436) > > at > > > reactor.core.publisher.MonoUsing$MonoUsingSubscriber.onComplete(MonoUsing.java:275) > > at > > > reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onComplete(Operators.java:2205) > > at > > > reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onComplete(Operators.java:2205) > > at > > > reactor.core.publisher.FluxHide$SuppressFuseableSubscriber.onComplete(FluxHide.java:147) > > at > > > reactor.core.publisher.MonoIgnoreElements$IgnoreElementsSubscriber.onComplete(MonoIgnoreElements.java:89) > > at > > > reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onComplete(Operators.java:2205) > > at > > > reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onComplete(Operators.java:2205) > > at > > > reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onComplete(Operators.java:2205) > > at > > reactor.core.publisher.MonoRunnable.subscribe(MonoRunnable.java:50) > > at > > > reactor.core.publisher.MonoDeferContextual.subscribe(MonoDeferContextual.java:55) > > at reactor.core.publisher.Mono.subscribe(Mono.java:4444) > > at > > > reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onError(FluxOnErrorResume.java:103) > > at > > > reactor.core.publisher.MonoFlatMap$FlatMapMain.onError(MonoFlatMap.java:180) > > at > > > reactor.core.publisher.MonoFlatMap$FlatMapMain.onError(MonoFlatMap.java:180) > > at > > > reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.onError(MonoIgnoreThen.java:278) > > at > > > reactor.core.publisher.SerializedSubscriber.onError(SerializedSubscriber.java:124) > > at > > > reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.whenError(FluxRetryWhen.java:225) > > at > > > reactor.core.publisher.FluxRetryWhen$RetryWhenOtherSubscriber.onError(FluxRetryWhen.java:274) > > at > > > reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.onError(FluxContextWrite.java:121) > > at > > > reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.maybeOnError(FluxConcatMapNoPrefetch.java:326) > > at > > > reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.onNext(FluxConcatMapNoPrefetch.java:211) > > at > > > reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.onNext(FluxContextWrite.java:107) > > at > > > reactor.core.publisher.SinkManyEmitterProcessor.drain(SinkManyEmitterProcessor.java:471) > > at > > > reactor.core.publisher.SinkManyEmitterProcessor$EmitterInner.drainParent(SinkManyEmitterProcessor.java:615) > > at > > > reactor.core.publisher.FluxPublish$PubSubInner.request(FluxPublish.java:602) > > at > > > reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.request(FluxContextWrite.java:136) > > at > > > reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.request(FluxConcatMapNoPrefetch.java:336) > > at > > > reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.request(FluxContextWrite.java:136) > > at > > > reactor.core.publisher.Operators$DeferredSubscription.request(Operators.java:1717) > > at > > > reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.onError(FluxRetryWhen.java:192) > > at > > > reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:149) > > at > > > reactor.core.publisher.MonoHasElement$HasElementSubscriber.onNext(MonoHasElement.java:72) > > at > > > reactor.core.publisher.MonoSubscribeOn$SubscribeOnSubscriber.onNext(MonoSubscribeOn.java:146) > > at > > > reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) > > at > > > reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) > > at > > > reactor.core.publisher.MonoCallable$MonoCallableSubscription.request(MonoCallable.java:156) > > at > > > reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2341) > > at > > > reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onSubscribe(FluxOnErrorResume.java:74) > > at > > reactor.core.publisher.MonoCallable.subscribe(MonoCallable.java:48) > > at reactor.core.publisher.Mono.subscribe(Mono.java:4444) > > at > > > reactor.core.publisher.MonoSubscribeOn$SubscribeOnSubscriber.run(MonoSubscribeOn.java:126) > > at reactor.core.scheduler.WorkerTask.call(WorkerTask.java:84) > > at reactor.core.scheduler.WorkerTask.call(WorkerTask.java:37) > > at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317) > > at > > > java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) > > at > > > java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) > > at > > > java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) > > at java.base/java.lang.Thread.run(Thread.java:1623) > > 21:55:39.885 [ERROR] o.a.j.i.p.AbstractMailboxProcessor - Unexpected > > error during IMAP processing > > org.apache.openjpa.persistence.PersistenceException: Multiple > > concurrent threads attempted to access a single broker. By default > > brokers are not thread safe; if you require and/or intend a broker to > > be accessed by more than one thread, set the openjpa.Multithreaded > > property to true to override the default behavior. > > at > > org.apache.openjpa.kernel.BrokerImpl.endOperation(BrokerImpl.java:2083) > > at > > org.apache.openjpa.kernel.BrokerImpl.isActive(BrokerImpl.java:2028) > > at > > > org.apache.openjpa.kernel.DelegatingBroker.isActive(DelegatingBroker.java:521) > > at > > > org.apache.openjpa.persistence.EntityManagerImpl.isActive(EntityManagerImpl.java:812) > > at > > > org.apache.openjpa.persistence.PersistenceExceptions$2.translate(PersistenceExceptions.java:82) > > at > > > org.apache.openjpa.kernel.DelegatingBroker.translate(DelegatingBroker.java:108) > > at > > > org.apache.openjpa.kernel.DelegatingBroker.isActive(DelegatingBroker.java:523) > > at > > > org.apache.openjpa.persistence.EntityManagerImpl.isActive(EntityManagerImpl.java:812) > > at > > > org.apache.james.mailbox.jpa.JPATransactionalMapper.rollback(JPATransactionalMapper.java:81) > > at > > > org.apache.james.mailbox.store.transaction.TransactionalMapper.lambda$executeReactive$1(TransactionalMapper.java:52) > > at > > > com.github.fge.lambdas.consumers.ConsumerChainer.lambda$sneakyThrow$9(ConsumerChainer.java:73) > > at reactor.core.publisher.Mono.lambda$doOnError$20(Mono.java:2741) > > at > > > reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onError(MonoPeekTerminal.java:250) > > at > > > reactor.core.publisher.MonoPeekTerminal$MonoTerminalPeekSubscriber.onError(MonoPeekTerminal.java:258) > > at > > > reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.onError(MonoIgnoreThen.java:278) > > at > > > reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.subscribeNext(MonoIgnoreThen.java:255) > > at > > reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:51) > > at > > > reactor.core.publisher.InternalMonoOperator.subscribe(InternalMonoOperator.java:64) > > at > > > reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:165) > > at > > > reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onNext(FluxSwitchIfEmpty.java:74) > > at > > reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:122) > > at > > > reactor.core.publisher.MonoSubscribeOn$SubscribeOnSubscriber.onNext(MonoSubscribeOn.java:146) > > at > > > reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) > > at > > > reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) > > at > > > reactor.core.publisher.MonoCallable$MonoCallableSubscription.request(MonoCallable.java:156) > > at > > > reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2341) > > at > > > reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onSubscribe(FluxOnErrorResume.java:74) > > at > > reactor.core.publisher.MonoCallable.subscribe(MonoCallable.java:48) > > at reactor.core.publisher.Mono.subscribe(Mono.java:4444) > > at > > > reactor.core.publisher.MonoSubscribeOn$SubscribeOnSubscriber.run(MonoSubscribeOn.java:126) > > at reactor.core.scheduler.WorkerTask.call(WorkerTask.java:84) > > at reactor.core.scheduler.WorkerTask.call(WorkerTask.java:37) > > at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317) > > at > > > java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304) > > at > > > java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) > > at > > > java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) > > at java.base/java.lang.Thread.run(Thread.java:1623) > > Suppressed: org.apache.openjpa.persistence.PersistenceException: > > Multiple concurrent threads attempted to access a single broker. By > > default brokers are not thread safe; if you require and/or intend a > > broker to be accessed by more than one thread, set the > > openjpa.Multithreaded property to true to override the default behavior. > > at > > org.apache.openjpa.kernel.BrokerImpl.endOperation(BrokerImpl.java:2083) > > at > > org.apache.openjpa.kernel.BrokerImpl.isActive(BrokerImpl.java:2028) > > at > > > org.apache.openjpa.kernel.DelegatingBroker.isActive(DelegatingBroker.java:521) > > at > > > org.apache.openjpa.persistence.EntityManagerImpl.isActive(EntityManagerImpl.java:812) > > at > > > org.apache.openjpa.persistence.PersistenceExceptions$2.translate(PersistenceExceptions.java:82) > > at > > > org.apache.openjpa.kernel.DelegatingBroker.translate(DelegatingBroker.java:108) > > at > > > org.apache.openjpa.kernel.DelegatingBroker.begin(DelegatingBroker.java:1028) > > at > > > org.apache.openjpa.persistence.EntityManagerImpl.begin(EntityManagerImpl.java:684) > > at > > > org.apache.james.mailbox.jpa.JPATransactionalMapper.begin(JPATransactionalMapper.java:59) > > ... 25 common frames omitted > > Wrapped by: org.apache.james.mailbox.exception.MailboxException: > > Begin of transaction failed > > at > > > org.apache.james.mailbox.jpa.JPATransactionalMapper.begin(JPATransactionalMapper.java:61) > > at > > > com.github.fge.lambdas.runnable.RunnableChainer.lambda$sneakyThrow$215(RunnableChainer.java:71) > > at reactor.core.publisher.MonoRunnable.call(MonoRunnable.java:73) > > at reactor.core.publisher.MonoRunnable.call(MonoRunnable.java:32) > > at > > > reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.subscribeNext(MonoIgnoreThen.java:252) > > ... 21 common frames omitted > > --------------------------------------------------------------------- > To unsubscribe, e-mail: server-user-unsubscr...@james.apache.org > For additional commands, e-mail: server-user-h...@james.apache.org > >
