Hi, On Wed, Dec 23, 2020 at 12:59 AM frank picabia <fpicabia@xxxxxxxxx> wrote: > > > Thanks for the responses. > > We'll take this up with VMware support and then if it isn't a configuration issue, move it along to Redhat Linux support. > > It was also useful to learn cgroups default support within the kernel can use up so much memory on a system with larger RAM. On the next reboot this will free up about 1.6 GB RAM. It might help with a little wiggle room until we know more about the other issue which seems to limit us to 1/2 our RAM. I'm not sure, but the kernel parameter vm.zone_reclaim_mode and/or NUMA memory interleaving may have an effect. regards, > > > On Mon, Dec 21, 2020 at 9:27 PM Tom Lane <tgl@xxxxxxxxxxxxx> wrote: >> >> frank picabia <fpicabia@xxxxxxxxx> writes: >> > My VMware admin has come back with a graph showing memory use over >> > the period in question. He has looked over other indicators >> > and there are no alarms triggered on the system. >> > It jives with what Cacti reported. Memory was never exhausted >> > and used only 50% of allocated RAM at the most. >> >> > If it's not a configuration issue in Postgres, and both internal and >> > external tools >> > show memory was not consumed to the point of firing off the "cannot fork" >> > error, would that mean that there is a bug in either the kernel or Postgres? >> >> [ shrug... ] Postgres is just reporting to you that the kernel wouldn't >> perform a fork(). Since you've gone to great lengths to show that >> Postgres isn't consuming excessive resources, either this is a kernel bug >> or you're running into some kernel-level (not Postgres) allocation limit. >> I continue to suspect the latter. Desultory googling shows that VMware >> can be configured to enforce resource allocation limits, so maybe you >> should be taking a hard look at your VMware settings. >> >> regards, tom lane -- Tatsuhito Kasahara kasahara.tatsuhito _at_ gmail.com
