On 1/16/23 08:26, Laurenz Albe wrote:
On Mon, 2023-01-16 at 09:30 +0100, Robert Sjöblom wrote:
We have a fleet of postgres 10 servers (1 primary, 2 replicas) that
we're now planning to upgrade. We've historically been forced to use the
same distro (centos7) and libc version, or rely on pg_dump/restore,
across pg versions due to the fact that the servers/databases were
initialized with the following options:
--lc-collate=sv_SE.UTF-8
We're upgrading all servers to pg15 through logical replication, and
with that we'd like to remove our dependency on any specific libc
version (to avoid corruption issues etc). We hope to do this by
initializing our pg15 clusters with swedish icu locale
(--icu-locale=sv-SE-x-icu). By using icu like this, we should have the
same sorting behavior as the pg10 servers have today? By our
understanding, we then should be able to use physical replication across
different OS versions, without worrying about index corruption etc?
According to
http://peter.eisentraut.org/blog/2022/09/26/icu-features-in-postgresql-15,
we still need to set a regular libc locale/option; does this mean that
the dependency on libc is still present as it pertains to corruption
issues and being forced to use the same libc version across all replicas?
I'd say no. The problem is the collation, and for that, the ICU
collation will be used.
check
The libc locale is for other aspects of locale.
Although I am not aware of any specific/known issues, keep in mind that
there is still a possibility of changes across major glibc versions for
things affected by LC_CTYPE, LC_TIME, LC_MONETARY, and LC_NUMERIC -
lower()/upper() for example.
--
Joe Conway
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
