Re: PG10 - Out of shared memory / invalid memory alloc request size

/proc/sys/kernel/shmax = 68719476736

On Tue, Nov 14, 2017 at 2:53 PM, Alvaro Aguayo Garcia-Rada <
aaguayo(at)opensysperu(dot)com> wrote:

> I remember an old issue I had with postgres and shared memory being set
> too low by the distro I was using.
>
> What's the value of "/proc/sys/kernel/shmmax"? Try setting to
> 18446744073709551615
>
> Regards,
>
> Alvaro Aguayo
> Operations Manager
> Open Comb Systems E.I.R.L.
>
> Office: (+51-1) 3377813 | Mobile: (+51) 995540103 | (+51) 954183248
> Web: www.ocs.pe
>
> ----- Original Message -----
> From: "Arjun Ranade" <ranade(at)nodalexchange(dot)com>
> To: "pgsql-admin" <pgsql-admin(at)postgresql(dot)org>
> Sent: Tuesday, 14 November, 2017 14:44:08
> Subject: [ADMIN] PG10 - Out of shared memory / invalid memory alloc
> request size
>
> We recently upgraded a database that a number of developers use from
> Postgres 9.4 to 10. Our memory parameters are unchanged.
>
> We are seeing a lot of errors that look like this in the postgres log:
>
> < 2017-11-14 13:13:59 EST [144172] : [1-1]
> user=[unknown],db=qa16,remote=192.168.104.22(35238) > FATAL: no
> PostgreSQL
> user name specified in startup packet
> < 2017-11-14 13:52:22 EST [6273] : [1-1]
> user=deployment_app,db=qa5,remote=192.168.104.83(45384) > ERROR: out of
> shared memory
> < 2017-11-14 14:17:53 EST [6200] : [3-1]
> user=service_tracker_app,db=qa16,remote=192.168.104.22(46996) > ERROR:
> invalid memory alloc request size 34359738368
>
> Anecdotally it seems that these errors are happening when
> powa_take_snapshot() (Postgres workload analyzer) is running as well but I
> can't confirm that.
>
> Does anyone know how to debug these types of errors? And once the db is in
> this state, how do we resolve sessions reporting "Error: invalid memory
> alloc request size" - killing the sessions and having them reconnect does
> not fix the issue.
>
> Thanks,
> Arjun
>