问题
Environment: Apache-tomcat-7.0.53, CentOS release 6.6 (Final), Java 1.8, Mongo 2.6
Design of our App
We have most of the calls handled with normal servlets(traditional synchronous ones). We do have a 2 asynchronous servlets(servlet 3.0) which delegate their work to ThreadPoolExecutors(threads named http-async-workers).
Problem:
We have a database heavy application, but it was performing quite well until 3500ccu.
But when we ramped up the CCU to 7000CCU, to measure the scalability factor, we have a lot waiting at the following method org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.register
This is the profiler snapshot:
This is the blocked threads view:
This is the how the threads look like(most of the them are blocked)
Query
Why is org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.register blocked than the database calls? Is it just a symptom of the db issues or the problem itself.
Any help is much appreciated.
来源：https://stackoverflow.com/questions/29035095/so-many-tomcat-http-worker-threads-are-blocked-especially-org-apache-coyote-abs