Re: Restoring from PostgreSQL 9.5 dump to 10 is super slow

Tried restoring to pg10 with maintenance_work_mem=1GB. No change in runtime.
When tried same on pg9.5 it ran couple of minutes faster than previous run.

Now I am going to turn off autovacuum and see if that makes any difference.

On Tue, May 7, 2019 at 10:38 AM Siddharth Karandikar
<siddharth.karandikar@gmail.com> wrote:
>
> Hi Andres,
>
> On Mon, May 6, 2019 at 8:09 PM Andres Freund <andres@anarazel.de> wrote:
> >
> > Hi,
> >
> > On 2019-05-06 16:54:08 +0530, Siddharth Karandikar wrote:
> > > I am trying to restore database dump created on PostgreSQL 9.5.16 to
> > > PostgreSQL 10.7 and it is taking a lot of time to restore. Restoring
> > > the same dump to 9.5 doesn't take that much. So I am wondering what
> > > could be reason behind this slowness.
> >
> > Is there any chance the configuration is different between 9.5 and 10?
> I double checked, but there is no difference in configurations of 9.5
> and 10. 9.5 restore works fine
> with maintenance_work_mem set to 16MB.
>
> But I will rerun restore on 10 with higher maintenance_work_mem.
>
> > If there e.g. is an index on the table, the maintanance_work_mem setting
> > would make a large differerence when rebuilding.  Note that the
> > medium-tablecase is noticably faster in 10 and that there's been some
> > speedup work around that in 10.
> >
> > >
> > > Postgres configuration that I have on this setup:
> > >     shared_buffers = 128MB
> > >
> > >     work_mem             = 1MB
> > >     maintenance_work_mem = 16MB
> >
> > maintenance_work_mem = 16Mb is a very low value - it's e.g. used for
> > index builds, to sort the data.
> >
> > Greetings,
> >
> > Andres Freund