upgrading and pg_restore versions

On Jan 4, 2007, at 2:42 PM, Angva wrote:

Dear Postgres gurus,

I come seeking advice on upgrading my 8.1.2 databases to 8.2. My
environment in a nutshell: I have a master database on one server that
is used to process large amounts of data. This data is replicated
daily
to several destination databases, each on a separate server. There are
so many destinations that I fear I won't be able to upgrade them
all in
one evening.

Does anyone know if it would be safe to upgrade a subset of the
databases per night? I am concerned with version mismatches between
dmp
files, pg_restore, and destination database versions. Should the
pg_restore still work ok? And if that is ok, should the master
database
be upgraded in any particular order (before or after the
destinations)?

I would greatly appreciate any advice that can be offered.

Thanks!
Mark

A few questions:

1. How is the data being replicated?
2. Is each slave getting all the data?

I would expect it to be easier to upgrade each slave as you have time
to do so, depending on how you're moving your data around. Later
versions of pg_dump usually play nicely with older versions of
postgres, whereas older pg_dump clients don't usually play nicely
with newer versions of postgres.

The nice thing about pg_dump is that you can output in SQL/DDL
format, which should usually be able to be restored into a different
version of postgres (possibly requiring edits to the dump file to
work around any incompatibilities). You don't have to rely on
pg_restore.

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