Hey Hugo, Hard to say without more information but we have experienced containers being killed like you described and solved it by setting -XX:MaxDirectMemorySize.
Jena/TDB storage makes use of memory mapped files https://jena.apache.org/documentation/tdb/store-parameters.html#file-access---mapped-and-direct-modes by default so this has an effect on overall memory usage inside the container that is not immediately apparent when observing JVM stats. Conal IOTICS On Wed, 1 Nov 2023, 19:43 Hugo Mills, <[email protected]> wrote: > Hi, > > > > We’ve got an application we’ve inherited recently which uses a Fuseki > database. It was originally Fuseki 3.4.0, and has been upgraded to 4.9.0 > recently. The 3.4.0 server needed regular restarts (once a day) in order to > keep working; the 4.9.0 server is even more unreliable, and has been > running out of memory and being OOM-killed multiple times a day. This > afternoon, it crashed enough times, fast enough, to make Kubernetes go into > a back-off loop, and brought the app down for some time. > > > > We’re using OpenJDK 19. The JVM options are: “-Xmx:30g -Xms18g”, and the > container we’re running it in has a memory limit of 31 GiB. We tried the > “-XX:+UserSerialGC” option this evening, but it didn’t seem to help much. > We see the RAM usage of the java process rising steadily as queries are > made, with occasional small, but insufficient, drops. > > The store is somewhere around 20M triples in size. > > > > Could anyone suggest any tweaks or options we could do to make this more > stable, and not leak memory? We’ve downgraded to 3.4.0 again, and it’s not > running out of space every few minutes at least, but it still has an > ever-growing memory usage. > > > > Thanks, > > Hugo. > > > > *Dr. Hugo Mills* > > Senior Data Scientist > > [email protected] > > > [image: Text Description automatically generated] > > *NEWS: *Visit our Data Marketplace > <https://app.agrimetrics.co.uk/catalog/> to explore our agrifood data > catalogue. > > www.agrimetrics.co.uk > <https://agrimetrics.co.uk/>[image: Icon Description automatically > generated] <https://www.linkedin.com/company/agrimetrics>[image: Icon > Description automatically generated with medium confidence] > <https://twitter.com/agrimetrics> > > > > > > >
