On 2017-11-21 18:50:05 -0500, Tom Lane wrote: > Andres Freund <andres@xxxxxxxxxxx> writes: > > On 2017-11-21 18:21:16 -0500, Tom Lane wrote: > >> Justin Pryzby <pryzby@xxxxxxxxxxxxx> writes: > >>> As $subject: backends are stuck in startup for minutes at a time. I didn't > >>> strace this time, but I believe last time I saw one was waiting in a futex. > > > A futex? Hm, that was stock postgres? > > Sure, since we switched to unnamed-POSIX semaphores in v10. On Linux > those are futexes. > (If Justin saw that while still on 9.6, then it'd be worth looking > closer.) Right. I took this to be referring to something before the current migration, but I might have overinterpreted things. There've been various forks/ports of pg around that had hand-coded replacements with futex usage, and there were definitely buggy versions going around a few years back. Greetings, Andres Freund
