[AMQ-5598] MQTT+NIO+SSL: Concurrent connections lead to 100% CPU usage

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Cannot Reproduce
• Affects Version/s: 5.10.0, 5.11.0
• Component/s: MQTT
• Labels: performance security

Environment

Red Hat Enterprise Linux Server release 6.6 (Santiago), Open JDK 64bit 1.7.0.75, 3Gig RAM, 30Gig HDD - 1x ActiveMQ 5.10

Windows 7 x64, Java 64bit 1.7.0, 8Gig RAM, 1x ActiveMQ 5.10, 1x ActiveMQ 5.11

• Assignee: Unassigned
• Reporter: Josef Awad
• Created: 19/Feb/15 11:38
• Updated: 22/Apr/15 05:33
• Resolved: 02/Apr/15 22:56

Description

Connecting with multiple instances of mqtt clients via ssl at the same time causes the borker server to run on 100% CPU usage forever. Only restart of ActiveMQ helps. Thread count maximizes during connection attempt.

Critical: It doesn't matter if the certificate is valid or not, I am able to shut down the broker from one client with 500 concurrent connecting instances. The payload size is not important. The problem is somewhere at the ssl handshake located. Without ssl everything works fine. Single ssl connections work.

Similar issues (with older versions) described are here:

• http://activemq.2283324.n4.nabble.com/SSL-handshake-stalls-broker-with-NIO-td4677916.html
• http://stackoverflow.com/questions/19395769/activemq-mqtt-maxes-cpu-on-first-client-connect