Hi, On 2018-07-19 15:39:44 -0400, Alvaro Herrera wrote: > On 2018-Jul-19, Amit Kapila wrote: > > > On Thu, Feb 22, 2018 at 7:55 PM, Robert Haas <robertmh...@gmail.com> wrote: > > > On Wed, Feb 21, 2018 at 10:03 PM, Mithun Cy <mithun...@enterprisedb.com> > > > wrote: > > >> seeing futex in the call stack andres suggested that following commit > > >> could > > >> be the reason for regression > > >> > > >> commit ecb0d20a9d2e09b7112d3b192047f711f9ff7e59 > > >> Author: Tom Lane <t...@sss.pgh.pa.us> > > >> Date: 2016-10-09 18:03:45 -0400 > > >> > > >> Use unnamed POSIX semaphores, if available, on Linux and FreeBSD. > > > > Hmm. So that commit might not have been the greatest idea. > > > > It appears so. I think we should do something about it as the > > regression is quite noticeable. > > So the fix is just to revert the change for the linux makefile? Sounds > easy enough, code-wise. Do we need more evidence that it's harmful? > > Since it was changed in pg10 not 11, I don't think this is an open-item > per se. (Maybe an "older bug", if we must really have it there.)
I'm a bit hesitant to just revert without further evaluation - it's just about as likely we'll regress on other hardware / kernel versions. Except it'd be in a minor release, whereas the current issue was in a major release. It'd also suddenly make some installations not start, due to sysv semaphore # limitations. There've been a few annoying, and a few embarassing, issues with futexes, but they receive far more attention from a performance POV. Greetings, Andres Freund
