Blocked Threads

We have an Ignition Gateway that seems to die a slow death over the course of a couple of hours. It then restarts and the process begins again. The symptoms that we see are high CPU utilization on the Gateway Status page. We see threads accumulating on the threads page with a state of Blocked. We’ve deployed this application to a number of sites and this is the first that has experienced this problem. This is a Perspective application running on Ignition v8.1.3 and incorporating SepaSoft OEE/Performance. Is there a way to determine what these threads are and what resource they seemed to be blocked by?

The definitive answer is to use Flight Recorder or the JDK’s debugging tools to examine the problem threads. Not particularly simple to execute. Support can probably help with those.

In the meantime, these topics might help you trim the list of possible culprits:

In addition to Phil’s suggestion an easy place to start would be to download a thread dump from the threads page once the blocked threads begin accumulating and post it here for us to look at. Sometimes blocked threads are expected or otherwise okay, sometimes they aren’t.

Kevin I thought I better check back in on this topic. The problem we were seeing just disappeared and we cannot explain what started the situation or what ended it at this point.