Hi, thanks for your reply. The problem only occurs when serving things that doesn't have any writes. Like static files or JSON structures from Pyramid. But essentially the problem would be the same. If pyramid_zodbconn expects a transaction manager to exist and it never got attached as a request callback then that problem would occur.
Does anyone know if any new mechanism as been applied around transactions to try to weed out situations where no transaction should be required? All the best, Robin 2017-03-23 19:25 GMT+01:00 Jonathan Vanasco <jonat...@findmeon.com>: > > > On Saturday, March 11, 2017 at 10:14:11 AM UTC-5, Robin Harms Oredsson > wrote: >> >> The only pattern I've really found seems to be: >> - It always happens on aborts >> - It seems to be during some server load >> - It only seems to happen during requests that only read data >> > > I don't use ZODB, but I may have an idea on where to look / possible ways > to create a repeatable test-case. > > I think I've seen similar situations caused by transaction deadlocks or > timeouts on readers high-concurrency situations when there is an extended > write going on. > > for example, there are 50 connections reading and 1 connection writing. > sometimes the writer would grab a table/row lock for too long, which would > cause a pileup of locks on the readers and a few would eventually fail. > under pyramid, the finished callbacks unconditionally fire after a request > -- including timeouts and errors where there was never a properly setup > transaction or database to cleanup. So it would try to abort, but it never > got started in the first place. > > this may be related to what you're experiencing. > > -- > You received this message because you are subscribed to the Google Groups > "pylons-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to pylons-devel+unsubscr...@googlegroups.com. > To post to this group, send email to email@example.com. > Visit this group at https://groups.google.com/group/pylons-devel. > For more options, visit https://groups.google.com/d/optout. > -- Betahaus phone: +46 70-333 00 10 web: http://www.betahaus.net -- You received this message because you are subscribed to the Google Groups "pylons-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to pylons-devel+unsubscr...@googlegroups.com. To post to this group, send email to firstname.lastname@example.org. Visit this group at https://groups.google.com/group/pylons-devel. For more options, visit https://groups.google.com/d/optout.