Re: Excellent job!

Kasia Tuszynska wrote:
> Mladen,
> You used pg_upgrade to migrate to 9.0?
> I ,perhaps mistakenly, assumed that it is for use once the db is at 9.0 to migrate in the future.
> Kasia
>
Yes, I did use pg_uprade. The purpose of pg_upgrade is to migrate from
the earlier releases to PgSQL 9.0. It works flawlessly with 8.4.4.
having in mind the size of the database, I used pg_upgrade --link, which
makes it impossible to re-open the database with the version 8.4.4.
Basically, you define (and export, of course) the following environment
variables:

OLDATADIR, pointing to 8.4.4 $PGDATA, typically ~postgres/data on Red
Hat systems.
OLDBINDIR, the directory where the old 8.4.4 binaries are, typically
/usr/bin on Red Hat systems.
NEWDATADIR, located at ~postgres/9.0/data on Red Hat systems.
NEWBINDIR, located at /usr/pgsql-9.0/bin on Red Hat systems.

After that, pg_upgrade will copy your old database to the new $PGDATA,
unless you specify "--link", in which case it will just create links.
The latter is much faster but much more dangerous. They say that speed
kills, but I had no problems whatsoever. Also, make sure that you have
all of the same languages installed on the new postgresql 9.0 as are
installed on postgres 8.x that you are migrating from. If you have
plperl or plpython on the 8.4 cluster, than you have to install it on
your 9.0 version or the pg_upgrade utility will refuse to cooperate and
will complain about the missing library.

--

Mladen Gogala
Sr. Oracle DBA
1500 Broadway
New York, NY 10036
(212) 329-5251
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