On Fri, Apr 14, 2017 at 1:50 PM, Moreno Andreo <moreno.and...@evolu-s.it> wrote:
> Sorry, > my mistake (I'm a bit nervous...) > > that's not work_mem, but shared_buffers > > Thanks > > > Il 14/04/2017 19:33, Melvin Davidson ha scritto: > > > > On Fri, Apr 14, 2017 at 1:12 PM, Moreno Andreo <moreno.and...@evolu-s.it> > wrote: > >> Hi all, >> About 2 hours and half ago, suddenly (and on the late afternoon of the >> Easter Friday), customers reported failing connections to our server, or >> even very slow. >> After a bit of checking (that also involved server reboot) I noticed >> (using top) that every process regarding postgres is using exactly the >> amout I configured as work_mem (3 GB). And AFAIK it's not good. >> >> 30085 postgres 20 0 *3370048* 156656 153876 S 6.7 0.3 0:00.20 postgres >> 29833 postgres 20 0 *3370000* 65260 62416 S 1.7 0.1 0:00.17 postgres >> 29632 postgres 20 0 *3372468* 11712 6028 S 0.7 0.0 0:00.60 postgres >> >> What can be happened? >> Nothing has been touched.... >> postgresql 9.5.6 on debian 8 just apt-get upgrade'd >> >> Any help would be appreciated. >> Moreno. >> > > > > *>using exactly the amout I configured as work_mem (3 GB). * > > > *You are right, that is bad, but that is your own fault. 3GB of work_mem > is very bad, Try lowing in to something more reasonable, like 20GB. * > > *https://www.postgresql.org/docs/9.5/static/runtime-config-resource.html#RUNTIME-CONFIG-RESOURCE-MEMORY > <https://www.postgresql.org/docs/9.5/static/runtime-config-resource.html#RUNTIME-CONFIG-RESOURCE-MEMORY> > "several running sessions could be doing such operations concurrently. > Therefore, the total memory used could be many times the value of work_mem; > it is necessary to keep this fact in mind when choosing the value."* > > -- > *Melvin Davidson* > I reserve the right to fantasize. Whether or not you > wish to share my fantasy is entirely up to you. > > > Moreno, we are working with minimal information here. Perhaps if you provided us with the following information it would be more useful, A. Total *SYSTEM MEMORY* B. shared_memory C. work_memory D. max_connections E. How many users were connected when the problem occurred? -- *Melvin Davidson* I reserve the right to fantasize. Whether or not you wish to share my fantasy is entirely up to you.