Re: AWS forcing PG upgrade from v9.6 a disaster

On Fri, May 28, 2021, 17:15 Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:

>
> On 5/28/21 4:23 PM, Jan Wieck wrote:
> > On 5/28/21 2:48 PM, Dean Gibson (DB Administrator) wrote:
> >
> > What sticks out for me are these two scans, which balloon from 50-60
> > heap fetches to 1.5M each.
> >
> >> -> Nested Loop (cost=0.29..0.68 rows=1
> >> width=7) (actual time=0.003..0.004 rows=1 loops=1487153)
> >> Join Filter: ("_IsoCountry".iso_alpha2 =
> >> "_Territory".country_id)
> >> Rows Removed by Join Filter: 0
> >> -> Index Only Scan using
> >> "_IsoCountry_iso_alpha2_key" on "_IsoCountry" (cost=0.14..0.38
> >> rows=1 width=3) (actual time=0.001..0.002 rows=1 loops=1487153)
> >> Index Cond: (iso_alpha2 =
> >> "_GovtRegion".country_id)
> >> Heap Fetches: 1487153
> >> -> Index Only Scan using
> >> "_Territory_pkey" on "_Territory" (cost=0.14..0.29 rows=1 width=7)
> >> (actual time=0.001..0.001 rows=1 loops=1487153)
> >> Index Cond: (territory_id =
> >> "_GovtRegion".territory_id)
> >> Heap Fetches: 1550706
> >
> > How did you load the database? pg_dump -> psql/pg_restore?
> >
> > If so, did you perform a VACUUM FREEZE after the load?
> >
> >
> >
>
> Jan
>
>
> AIUI he did an RDS upgrade. Surely that's not doing a dump/restore? I
> assume you would know better than him or me what it actually does do :-)
>

Since I am not working at AWS I can't tell for sure. ;)

It used to perform a binary pgupgrade. But that also has issues with xids
and freezing. So I would throw a cluster wide vac-freeze in there for good
measure, Sir.

Best Regards, Jan

>
> cheers
>
>
> andrew
>
>
> --
> Andrew Dunstan
> EDB: https://www.enterprisedb.com
>
>