@Jacques, let me check the performance test [1] results from the past with epoll disabled (or we have to re-run).
@Hanifi, With higher concurrency in performance testing, queries failed with this error: java.io.IOException: syscall:read(...)() failed: Connection reset by peer This is a known issue [2] with the version of Netty that Drill uses. I don’t think there is a specific ticket, but a search [3] shows a few relevant tickets. Thank you, Sudheesh [1] https://github.com/mapr/drill-perf-test-framework <https://github.com/mapr/drill-perf-test-framework> [2] https://github.com/netty/netty/issues/3539 <https://github.com/netty/netty/issues/3539>[3] https://issues.apache.org/jira/browse/DRILL-3119?jql=project%20%3D%20DRILL%20AND%20text%20~%20%22syscall%3Aread%22 <https://issues.apache.org/jira/browse/DRILL-3119?jql=project%20=%20DRILL%20AND%20text%20~%20%22syscall:read%22> > On Mar 25, 2016, at 11:44 AM, Hanifi Gunes <[email protected]> wrote: > > I am wondering what the issue and its manifestation was back then. Do we > have any JIRAs created for this before? > > > Thanks. > -Hanifi > > On Fri, Mar 25, 2016 at 9:57 AM, Jacques Nadeau <[email protected]> wrote: > >> Hey All, >> >> If I recall correctly, many months ago Sudheesh discovered that we were >> having instability in RPC connections in some situations due to bugs in the >> epoll implementation that are fixed in a later version of Netty (~4.0.31?). >> At the time, we shelved switching Netty because it also changed the memory >> caching behavior (same thread to all thread) which seemed like a high risk >> change. I thought that as part of this we decided the safest change was to >> disable epoll RPC in our distribution. However, reviewing drill-env, it >> doesn't look like we do this. See here [1]. >> >> Thoughts? >> >> [1] >> >> https://github.com/apache/drill/blob/master/distribution/src/resources/drill-env.sh#L19 >> -- >> Jacques Nadeau >> CTO and Co-Founder, Dremio >>
