Vert.x ( 1.5.7 ) warnings for thread blocked.

[iamakashk]

Hi
I am getting multiple warnings in logs like this.

WARN [vertx-blocked-thread-checker]: Thread Thread[vert.x-eventloop-thread-4,5,main] has been blocked for 3894 ms, time limit is 2000 ms WARN [vertx-blocked-thread-checker]: Thread Thread[vert.x-eventloop-thread-2,5,main] has been blocked for 14453 ms, time limit is 2000 ms io.vertx.core.VertxException: Thread blocked at sun.misc.Unsafe.park(Native Method) ~[?:1.8.0_292] at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) ~[?:1.8.0_292] at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836) ~[?:1.8.0_292] at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:870) ~[?:1.8.0_292] at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1199) ~[?:1.8.0_292] at java.util.concurrent.locks.ReentrantReadWriteLock$WriteLock.lock(ReentrantReadWriteLock.java:943) ~[?:1.8.0_292] at com.sun.jmx.mbeanserver.Repository.addMBean(Repository.java:416) ~[?:1.8.0_292] at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerWithRepository(DefaultMBeanServerInterceptor.java:1898) ~[?:1.8.0_292] at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:966) ~[?:1.8.0_292] at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:900) ~[?:1.8.0_292] at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:324) ~[?:1.8.0_292] at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:522) ~[?:1.8.0_292] at org.apache.commons.pool2.impl.BaseGenericObjectPool.jmxRegister(BaseGenericObjectPool.java:1059) ~[?:?] at org.apache.commons.pool2.impl.BaseGenericObjectPool.<init>(BaseGenericObjectPool.java:141) ~[?:?] at org.apache.commons.pool2.impl.GenericObjectPool.<init>(GenericObjectPool.java:105) ~[?:?]

Is this something normal to ignore or is there any configuration that needs to be done ?

Thanks for the help in advance.
Just FYU I am facing similar issue mentioned over here.

[msavy]

It suggests that you have something that is blocking up a Vert.x event loop thread for a very long time.

This is extremely bad for performance as Vert.x is based on the reactor model, and locking an event loop thread will block that reactor's entire handler queue until whatever is doing the blocking releases it. Effectively taking an entire core out of action for a while.

It looks like you're doing something blocking with JMX in your policy perhaps?

[iamakashk]

Ohh yes. I am using redis to store stats related to every incoming request. I will check on that implementation and let you know if this gets resolved.

Thanks for the help. :)

[iamakashk]

Hey @msavy
Issue was in policy which I was using. Corrected it and its working fine now. Thanks 😊