Re: 15 pg_upgrade with -j - Mailing list pgsql-general

From Jeff Ross
Subject Re: 15 pg_upgrade with -j
Date
Msg-id 79a10835-e830-51f0-bdc1-596807aa5b7a@openvistas.net
Whole thread Raw
In response to Re: 15 pg_upgrade with -j  (Adrian Klaver <adrian.klaver@aklaver.com>)
List pgsql-general
On 5/22/23 5:43 PM, Adrian Klaver wrote:


From docs:

https://www.postgresql.org/docs/current/pgupgrade.html

The --jobs option allows multiple CPU cores to be used for copying/linking of files and to dump and restore database schemas in parallel; a good place to start is the maximum of the number of CPU cores and tablespaces. This option can dramatically reduce the time to upgrade a multi-database server running on a multiprocessor machine.

So is the 1400G mostly in one database in the cluster?


The full commands we are using for pg_upgrade are pretty stock:

Yes, one big database with about 80 schemas and several other smaller databases so -j should help, right?


As I understand it no. That the parallelism is between databases not within a database. Further that 'database schemas' refers to schema as the overall database object definitions not the namespaces known as schemas in the database.

Thanks Adrian.  That "restore database schemas in parallel" phrase seems like it would be really easy to read like we did and expect it to work with one database and multiple schemas.

Maybe it should be changed to "restore multiple databases in parallel" instead?

Jeff

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