Justin Pryzby <pryzby@xxxxxxxxxxxxx> writes: > We never had any issue during the ~2 years running PG96 on this VM, until > upgrading Monday to PG10.1, and we've now hit it 5+ times. > BTW this is a VM run on a hypervisor managed by our customer: > DMI: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 06/22/2012 > Linux TS-DB 2.6.32-431.el6.x86_64 #1 SMP Fri Nov 22 03:15:09 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux Actually ... I was focusing on the wrong part of that. It's not your hypervisor, it's your kernel. Running four-year-old kernels is seldom a great idea, and in this case, the one you're using contains the well-reported missed-futex-wakeups bug: https://bugs.centos.org/view.php?id=8371 While rebuilding PG so it doesn't use POSIX semaphores will dodge that bug, I think a kernel update would be a far better idea. There are lots of other known bugs in that version. Relevant to our discussion, the fix involves inserting a memory barrier into the kernel's futex call handling: https://github.com/torvalds/linux/commit/76835b0ebf8a7fe85beb03c75121419a7dec52f0 regards, tom lane
