Backend cache causing display issues

[BanditBBS]

Ok, so I have ~1400 hosts and ~31000 services and thought I should try the backend cache. I just added 4 new hosts and 23 services per host and applied the changes. After everything was back up I searched for the hostnames(all start with same set f characters) and hit enter. I was shown the list of the 4 hosts with all the services under them. Then when the screen auto refreshed they all disappeared. Then I searched again and nothing. Waited a few seconds and then I got the hosts with no services. Waited 30 seconds or so and got everything again. Then circle back around and do it all over again and again. Finally I just shut off the cache and all is fine.

[jomann]

Interesting, is the location that you're storing the cache on just regular disk? We did testing on the back-end caching on a server of pretty similar size but didn't have display issues. Can you let me know what you set your back-end settings to with a screenshot of the settings screen just to see if something weird was going on?

[BanditBBS]

I just checked the checkbox and hit save. I used the default including using ramdisk.

[jomann]

Re-reading what you did, I think it may be a bug in the way that the caching works, so I will add it in TPS for us to test and look into in-house. It should have shown the services once the back-end cache was cleared based on the time value for sure (I think it's set to 5 min by default) but for whatever reason wasn't updating your cache files.

[bheden]

Bandit,

I couldn't replicate specifically what it is that you experienced, but it makes sense to me.

Technical geek stuff:

The way the cache works is that whenever XI is trying to grab a chunk of data, it checks to see if an existing cache (XML file) with the exact parameters is found. If it is found, and it is within the allotted time frame, it simply returns that data (the file likely didn't contain any references to your new hosts and services). This can potentially teeter back and forth a few times before the data is mostly accurate.

Solution:

The caching shouldn't really be used in a system that is going to change frequently. That seems to be begging for trouble. I should have listed this as an important note on the Backend Cache settings page. I'll update that now for 5.3.1.

Thanks!