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

On 2021-05-28 13:23, 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?
>
> Regards, Jan

It was RDS's "upgrade in place".  According to the PostgreSQL site, for
v9.4 & v12: /"Aggressive freezing is always performed when the table is
rewritten, so this option is redundant when //|FULL|//is specified."/

I did a VACUUM FULL.