Coldfusion not expiring session with Redis

Curtis, I know you first chimed in today on the other long thread on Redis sessions that seemed not to be expiring (https://community.adobe.com/t5/coldfusion/redis-session-keys-not-expiring/m-p/11180920?page=1), and you opted to instead create this new post, in case this may be a "different" issue. I guess we'll see. 🙂

So first, did you at least catch and consider the extended reply I'd offered there, where I elaborated how one could watch things going on in Redis? That may help with your investigation of things. I do appreciate that mine and the comments from others did make for a lot of reading. I'm just wondering first if you're saying you did consider it all. If you did not, I'll come back to it in a moment.

But let's turn to your situation, that the sessions never seem to expire.

First, how are you tracking that? You may well just be simply testing pages. Hopefully you are waiting at least 30 mins between checks, as each call to such a page will restart the timeout clock to a new 30 mins. I know you say you find the sessions are there "after several hours of inactivity", so again just checking.

Perhaps you are watching with a tool like FusionReactor or the CF 2018 PMT?  If you are, that may be actually CAUSING the issue.

The mere act of having the PMT enabled and monitoring a CF instance has been known (and reported) to cause problems with CF sessions. It was reported first as a bug report and then as a blog post by the FusionReactor folks. They found it, and they stopped FR from tracking details of Redis sessions (though they still show the count).  Adobe has said as recently as last month that they have not yet resolved the issue yet.

Now, both those talk about the PERFORMANCE impact (high CPU) of some unexpected and excessive ACCESS by the monitoring tools to the Redis store, to track the sessions. Neither the tracker report nor the FR blog post speak of any impact on session timeouts (or unexpectedly keeping the session from timing out).

But that certainly COULD be happening. And that's why I asked if you are using either tool to monitor your CF instance, and if that's how you knew that sessions were "not timing out". If you ARE using either, what if you stopped?

As for FR, you don't really need to stop using FR, at least if using version 8.2.3 or above, as they stopped their impact. If you don't know if FR IS monitoring your CF instance, you can look in the CF Admin "java and jvm" page, and the java args field, to see if it refers at all to fusionreactor (you can also open the CF jvm.config file and look for it in there).

As for the PMT, you can't stop it being monitored from inside the CF Admin. Instead, you need to go to the PMT (wherever it's installed, which could be another machine) and tell it to STOP monitoring the CF instance in question. And if you may say that you don't know if the CF instance in question is being monitored by the PMT, you CAN find that by going to the PMT page in the CF Admin (use the new CF Admin search feature in CF2018 to find it). That PMT page has an indicator of whether the instance is being monitored by the PMT.

I do understand that "stopping the monitoring" may be a solution some will balk at. I'm simply proposing you do it for investigation sake, even if only for the hour needed to confirm if sessions do again start timing out.  (Just remember that they do only timeout after inactivity, not 30 mins after creation. So it's not unsual to have sessions last "longer than the timeout".)

If you might confirm that you don't have EITHER FR (older than 8.2.3) or the CF PMT monitoring this instance, I realize you may feel you are stuck. And perhaps others may have new information (none was offered in the other thread). But until then, I will again encourage you to use the Redis diagnostic tools that I referred to in my comment in the other thread.

Do let us know how things go.