From: Achilleas Mantzios <achill@matrix.gatewaynet.com>
Organization: Dynacom Tankers Mgmt
To: pgsql-admin@postgresql.org
Subject: Re: Ideal way to upgrade to postgres 8.3 with less downtime
Date: Fri, 7 Nov 2008 10:32:40 +0200
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Cc: "Swathi S" <ss.postgres@gmail.com>
References: <6c1264780811062204t260f7c4eo20675bc8d2b0bb6b@mail.gmail.com>
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=CE=A3=CF=84=CE=B9=CF=82 Friday 07 November 2008 08:04:05 =CE=BF/=CE=B7 Swa=
thi S =CE=AD=CE=B3=CF=81=CE=B1=CF=88=CE=B5:
> Hi,
>=20
> I have a database of size approx 400G. It's a 24/7 database. Only few tab=
les
> have regular reads and writes. The other tables just store information.
>=20
> I would like to upgrade to 8.3 and would like to know the best way to
> upgrade with less downtime.
>=20
> Thanks
> Swathi
>=20

And now you are running with which version?
The ideal way is to read the HISTORY file, do several upgrade excercises on=
 a test system with the
same database (e.g. with a recent backup of the original), and then plan/or=
ganize your actions.
But i must say that the older version of postgresql you run, the fancier th=
ings your apps do, and the more lines of code they have,
the harder it will be to upgrade.
Usually SPI and JDBC require large amounts of work as well.
Well i dont mean to be pessimistic, but our 7.4 -> 8.3 upgrade was pretty p=
ainful.

=2D-=20
Achilleas Mantzios