Hi List,
I'm making some tests in order to prepare a db migration. We have version 9.6 over CentOS 7 and we're going to migrate to version 15 over Rocky Linux 9. Of course there is a no downtime requirement or I wouldn't be here asking.
I was previously aware of the problem with different glibc version between systems before I started my tests, but I tried it anyway. I first upgraded CentOS version to 15 and then made a streaming replication to the other server (Rocky). After that I encountered the next warning when connecting to new hot standby database:
WARNING: database my_db has a collation version mismatch
DETAIL: The database was created using collation version 2.17, but the operating system provides version 2.34.
HINT: Rebuild all objects in this database that use the default collation and run ALTER DATABASE my_db REFRESH COLLATION VERSION, or build PostgreSQL with the right library version.
I tried what was suggested: reindexing and running "refresh collation" alter after that and everything seems to work ok so this looks like an easy wat to migrate from one server to another. Plus I feel more comfortable using streaming replication than logical replication, and also I find it more useful when you need to replicate the whole cluster.
So my question is: is there anything I'm missing here, some kind of problem that could hit my face after moving to the new server?
Thanks in advance,
Ekaterina