Re: Upgrade from PG12 to PG

correction: -k = --link

On 24/07/2023 14:59, Jef Mortelle wrote:
> Hello
>
> This is the syntax:
>
> export PGDATA=/pg/PG15/system
> export PATH=/usr/lib/postgresql15/bin:/bin:/usr/bin:/usr/local/bin
>
> export PGDATAOLD=/pg/data
> export PGDATANEW=/pg/PG15/system
> export PGBINOLD=/usr/lib/postgresql12/bin
> export PGBINNEW=/usr/lib/postgresql15/bin
>
> /usr/lib/postgresql15/bin/pg_upgrade -r -v -p 5431 -P 5432 -k -j 8
>
>  -r =--link
>
> Kind regards
>
> On 24/07/2023 14:52, Scott Ribe wrote:
>>> On Jul 24, 2023, at 12:38 AM, Jef Mortelle <jefmortelle(at)gmail(dot)com>
>>> wrote:
>>> For some reason Postgres creates a new subdirectory for each PG
>>> version (I make use of tablespaces for each database in my PG
>>> cluster), also with using the link option.
>>> So after some upgrade,  it ends in a really mess with directory's?
>> At the end of pg_upgrade, you can start up the old version against
>> the old directory, or the new version against the new directory.
>> (With --link, only until writing into the db, then you are committed
>> to the running version.) Once you are comfortable that everything is
>> good with the new version, you should delete the old data.
>> Alternatively, if there is a problem forcing you back to the old
>> version, you delete the new data.
>>
>>> => pg_dump schema_only, after RAM upgrade from 8GB up to 64GB
>>> (otherwise the query against pg_largeobject ends in a OUT of Memory
>>> error) runs in about 3-4 minutes
>>> => pg_restore takes 7 hours, which is 99% used for executing the
>>> query like:  SELECT pg_catalog.lo_unlink('oid');
>> Given the tests you've run, it seems to me that it is doing something
>> which it ought not when using --link.
>>
>>> Database is 95GB, so not so big ;-) but have ~25miljon large objects
>>> in it.
>> I suppose the use of large objects here is an artifact of support for
>> other databases which have much lower limits on varchar column length.
>>
>>