Re: Linux in-place upgrade

On Mon, 2023-06-26 at 17:13 +0000, Murthy Nunna wrote:
> We are planning an in-place upgrade of Linux level from RHEL 7 to RHEL 8 or RHEL 9.
> We have several PG clusters running on this server using different versions of postgres (pg12, pg13 and pg14).
>  
> We have couple of plans:
>  
>    1. Shutdown clusters, unmount disks that contain postgres data and wals, upgrade Linux,
>       remount postgres disks and restart postgres clusters
>    2. Same as above but reinstall postgres (pg12, pg13 and pg14) before restarting postgres clusters
>  
> Questions:
>    1. Will 1 or 2 or both above work?
>    2. Is there any official documentation above OS upgrades?

The documentation is here:
https://www.postgresql.org/docs/current/upgrading.html

It depends on how you installed PostgreSQL.  If you used binary packages, Option 1 should work fine.

Don't forget to reindex all indexes on strings!

It could be more than just indexes. If there are any partitioned tables with a partition key of a string, it

could be impacted too. There is a video from the recent PGCon about the collation changes that

happen going from RHEL7 to RHEL9.
https://www.pgcon.org/events/pgcon_2023/schedule/session/345-sorting-out-glibc-collation-challenges/