Re: Handling glibc v2.28 breaking changes

Hi Adrian,

Thank you for your quick response.

By zero downtime, I meant at least one of the three nodes is up at any time
to handle the writes and reads.

> Define how the 3 node cluster works?
These 3 nodes are configured as 1 primary, 1 sync replica and 1 async
replica. These are managed via stolon.

> What is the locale for the Postgres instances?
We are using en_US.UTF-8 collation.

> What is acceptable downtime in the process?
We want to minimize as little as possible since these will be customer
facing clusters.

> Are you using ICU collation?
As far as I know, ICU collation is supported from Postgres v10 but we are
still running v9.6 so I guess that is not an option unless we upgrade our
cluster first.

I am open to ways including changing architecture or upgrading cluster
first or evaluating logical replication or any other option but our primary
goal is to achieve it with minimal downtime.

Thank you for your help.
Best regards,
Pradeep

On Sun, Apr 24, 2022 at 11:43 PM Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> On 4/24/22 08:31, Pradeep Chhetri wrote:
> > Hello everyone,
> >
> > I am sure this has been discussed multiple times in the past but I would
> > like to initiate this discussion again. I have 3 nodes cluster of
> > Postgres v9.6. They all are currently running on Debian 9 (with glibc
> > v2.24) and need to upgrade them to Debian 10 (with glibc v2.28) without
> > downtime. In order to bypass the glibc issue, I am trying to evaluate
> > whether I can compile glibc v2.24 on Debian 10, pin postgres to use this
> > manually compiled glibc and upgrade the linux distribution in rolling
> > fashion. I would like to know how others have achieved such distro
> > upgrades without downtime. I am new to Postgres so please pardon my
> > ignorance.
>
> You are going to have to be more specific as upgrading a distro involves
> downtime. I'm guessing you mean downtime for Postgres, still at least
> one of the instances is going to be down while it's OS is being
> upgraded. So:
>
> 1) Define how the 3 node cluster works?
>
> 2) What is the locale for the Postgres instances?
>
> 3) What is acceptable downtime in the process?
>
> 4) Are you using ICU collation?
>
> Also you might want to look at:
>
> https://wiki.postgresql.org/wiki/Locale_data_changes
>
> >
> > Thank you for your help.
> > Best regards,
> > Pradeep
>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com
>