Hi,
Another thing that I want to bring up is, whenever I do `select * from
pg_stat_activity;`
Lot of times I see LWLock and WALWriteLock for wait_event_type and
wait_event respectively
on all 4 restore `COPY` jobs.
I would like to understand what exactly it is trying to indicate.
Could this be reason
behind slow restores?
On Tue, May 7, 2019 at 2:29 PM Siddharth Karandikar
<siddharth.karandikar@gmail.com> wrote:
>
> 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