Hi, > On 26.01.2016, at 14:28, Musall Maik <m...@selbstdenker.ag> wrote: > > Anyway, heap sizes of up to 60 GByte are apparently not so common, at least > not with WebObjects. I found a helpful article [1] about very large JVM > heaps, including the hint to the Zing Azul JVM, which features a stopless > garbage collector [3], but costs $8000 per server and year. In the end, we > may actually be trying that if other options fail, but first I need to > understand more about what's in memory. I'm currently approaching that > question via JProfiler, especially to find out if that's all snapshot cache > (how would I limit that in size?) or some other homemade memory leak.
Just a shot in the dark (especially the regular timing makes this weird), but we have had some issues with the snapshot cache accumulating a lot of data when some editing contexts weren't disposed early on (and the referred objects thus were carried on until session timeouts may finally remove them). With the number of objects growing we observed (if I remember correctly) quadratic runtime growth when retrieving objects form the snapshot cache. As we handle a large amount of small objects, this escalated rather suddenly when the cache exceeded a certain size. In this case JProfiler should show you larger amounts of time spent retrieving objects from the snapshot cache in the Hotspots list. In our case we were able to dispose editing contexts as soon as possible, flushing the objects out of the cache and keeping retrieval time speedy. Restarting instances would in this case also keep the accumulated cruft down, this scenario would probably only match though, if a significant amount of objects come into the system shortly before or at the waiting times. Greetings Dennis -- ----------------------------------------------------- Dennis Bliefernicht • Backend Development T +49 40 357 3001 62 dennis.blieferni...@xyrality.com XYRALITY GmbH • Friedensallee 290 • 22763 Hamburg www.xyrality.com <http://www.xyrality.com/> Registergericht: Hamburg HRB 115332 Geschäftsführer: Sven Ossenbrüggen -----------------------------------------------------
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