Github user shoukunhuai commented on the issue:
https://github.com/apache/activemq-artemis/pull/1899
So it is a mistake to use global thread pool instead of io thread pool for
page cursor.
But this does not fix our problem, as you can see
```
"Thread-274672
(ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$5@4e91d63f)"
Id=274703 TIMED_WAITING on java.util.concurrent.CountDownLatch$Sync@5c416651
at sun.misc.Unsafe.park(Native Method)
- waiting on java.util.concurrent.CountDownLatch$Sync@5c416651
at
java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
at
java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireSharedNanos(AbstractQueuedSynchronizer.java:1037)
at
java.util.concurrent.locks.AbstractQueuedSynchronizer.tryAcquireSharedNanos(AbstractQueuedSynchronizer.java:1328)
at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:277)
at
org.apache.activemq.artemis.core.journal.impl.SimpleWaitIOCallback.waitCompletion(SimpleWaitIOCallback.java:73)
at
org.apache.activemq.artemis.core.persistence.impl.journal.OperationContextImpl.waitCompletion(OperationContextImpl.java:313)
at
org.apache.activemq.artemis.core.persistence.impl.journal.AbstractJournalStorageManager.waitOnOperations(AbstractJournalStorageManager.java:294)
at
org.apache.activemq.artemis.core.paging.cursor.impl.PageCursorProviderImpl.storeBookmark(PageCursorProviderImpl.java:539)
at
org.apache.activemq.artemis.core.paging.cursor.impl.PageCursorProviderImpl.cleanupComplete(PageCursorProviderImpl.java:431)
at
org.apache.activemq.artemis.core.paging.cursor.impl.PageCursorProviderImpl.cleanup(PageCursorProviderImpl.java:383)
- locked
org.apache.activemq.artemis.core.paging.cursor.impl.PageCursorProviderImpl@4f8d6d9a
at
org.apache.activemq.artemis.core.paging.cursor.impl.PageCursorProviderImpl$1.run(PageCursorProviderImpl.java:291)
at
org.apache.activemq.artemis.utils.actors.OrderedExecutor.doTask(OrderedExecutor.java:42)
at
org.apache.activemq.artemis.utils.actors.OrderedExecutor.doTask(OrderedExecutor.java:31)
at
org.apache.activemq.artemis.utils.actors.ProcessorBase$ExecutorTask.run(ProcessorBase.java:53)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Number of locked synchronizers = 2
- java.util.concurrent.locks.ReentrantReadWriteLock$NonfairSync@613d010
- java.util.concurrent.ThreadPoolExecutor$Worker@4c03ae59
```
When exit paging state, we will store bookmark for each page subscription
and wait until all callbacks done.
I believe this may happen even running in io thread as long as
singleThreadExecutor in AbstractJournalStrorageManager use thread from global
server thread pool.
---
