Re: pg_attribute, pg_class, pg_depend grow huge in count and size with multiple tenants.

Hi all,

Since we are talking about multi-tenant databases, the citus extension
<https://www.citusdata.com/product/community> fits in neatly with that
using horizontal partitioning/shards.

Regards,
Michael Vitale

Avinash Kumar wrote on 5/8/2020 6:14 AM:
> Hi,
>
> On Fri, May 8, 2020 at 3:53 AM Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at
> <mailto:laurenz(dot)albe(at)cybertec(dot)at>> wrote:
>
> On Fri, 2020-05-08 at 03:47 -0300, Avinash Kumar wrote:
> > > Just set "autovacuum_max_workers" higher.
> >
> > No, that wouldn't help. If you just increase
> autovacuum_max_workers, the total cost limit of
> > autovacuum_vacuum_cost_limit (or vacuum_cost_limit) is shared by
> so many workers and it
> > further delays autovacuum per each worker. Instead you need to
> increase autovacuum_vacuum_cost_limit
> > as well when you increase the number of workers.
>
> True, I should have mentioned that.
>
> > But, if you do that and also increase workers, well, you would
> easily reach the limitations
> > of the disk. I am not sure it is anywhere advised to have 20
> autovacuum_max_workers unless
> > i have a disk with lots of IOPS and with very tiny tables across
> all the databases.
>
> Sure, if you have a high database load, you will at some point
> exceed the limits of
> the machine, which is not surprising.  What I am trying to say is
> that you have to ramp
> up the resources for autovacuum together with increasing the
> overall workload.
> You should consider autovacuum as part of that workload.
>
> If your machine cannot cope with the workload any more, you have
> to scale, which
> is easily done by adding more machines if you have many databases.
>
> Agreed. Getting back to the original question asked by Sammy, i think
> it is still bad to create 2000 databases for storing 2000
> clients/(schemas) for a multi-tenant setup.
>
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com
>
>
>
> --
> Regards,
> Avinash Vallarapu