It is hard to say as it only happens for 30s couple of times per day. Everything does return to normal after the blocking transaction is committed. It could be a disk thing or even a network issue (the java app is on a different machine to the db). But I never saw transactions blocked in commit before so was wondering if there is any rational set of reasons why it might do that. On Mon, 24 May 2021 at 15:09, Vijaykumar Jain <vijaykumarjain.github@xxxxxxxxx> wrote: > > No worries, > > There were some threads earlier which mentioned some automated changes to disk by the provider that resulted in some slowness. > > But otherwise also, do you query system, disk metrics. > > Do you see any anomaly in disk io (wait) when you saw blocking? > If it did, did the io return to normal when blocks were cleared ? > > > > On Mon, May 24, 2021, 7:23 PM Bob Jolliffe <bobjolliffe@xxxxxxxxx> wrote: >> >> Hello Jain >> >> Sorry forgot to indicate: it is running the ubuntu packaged version >> 13.3 on ubuntu 20.04. >> >> It is not in the cloud, but is a VM in a government datacentre. I am >> not sure of the underlying hyperviser. I could find out. >> >> Regards >> Bob >> >> >> On Mon, 24 May 2021 at 12:35, Vijaykumar Jain >> <vijaykumarjain.github@xxxxxxxxx> wrote: >> > >> > I think there have been similar issues reported earlier as well. But it would be too early to generalize. >> > >> > >> > Where is the db server running? Cloud? >> > >> > Also what is the version ? >> > >> > >> > On Mon, May 24, 2021, 5:00 PM Bob Jolliffe <bobjolliffe@xxxxxxxxx> wrote: >> >> >> >> I am seeing a strange issue on a database using jdbc. Regularly, 4 or >> >> 5 times a day, I see something like a "stutter", where a bundle of >> >> maybe 30 transactions suddenly finish at the same time. It looks like >> >> (it is quite hard to catch this exactly) that the lead transaction >> >> which has been blocking the rest has been blocked in COMMIT. In each >> >> case it blocks for almost exactly 30s, just over, and once it goes >> >> through, releases locks, and the others clear behind it. >> >> >> >> My question: what are the range of possibilities that might cause a >> >> COMMIT to block? I haven't seen this before. Is there anything >> >> suspicious about the regular 30s? Occasionally we see 60s, which >> >> seems likely to be two sets of 30. >> >> >> >> Regards >> >> Bob >> >> >> >>
