Re: Sobre Actualizacion

Hi Ricardo.

Remember you have to write in english in this forum. There is an
specific forum in spanish language if you prefer to use spanish instead
of english.

Anyway, migration from 7.4 to 8.x is not trivial. First you have to
decide what is your target version. It's not the same migrate to 8.1 or
8.2 that 8.3. Migrate to 8.0, 8.1 or 8.2 is relatively easy. You have to
perform an export of your database and import into new version. There
could minor problems if you use tsearch (y recommend you to install
tsearch in your new database before importing from 7.4) but basically
everything will go without problems.

Migration to 8.3 is not so easy... Well, the process is the same, but
due to changes in "tipado de los campos" you will probably have to
perform some changes in your application. With < 8.3, postgres
automatically converts data from some type (for example, an varchar) to
destination type without asking for it. However, with 8.3 you will have
to perform this conversion in an explicit way, that is, telling postgres
that you have to convert it. So if the queries of your application or
database functions or triggers were poorly designed (and believe me,
this is very frequent) you will have to adapt them to work with 8.3 or
higher. And in 8.3 tsearch2 has been included in core, so you will have
to change tsearch calls or at least install the "translation" package.

But, of course, 8.3 performance is quite better that 8.2 or 8.1. So, I
will try first with 8.3 and if you don't have problems or your
application doesn't require many changes, use it.

We migrated gforge 4.5 from postgres 7.4 to 8.1 two years ago and it was
quite hard since we have to modify parts of data model and clean our
database since there were strange characters inserted in our tables. We
have planned to migrate to 8.3 this year, but we should modify gforge in
order to acomplish with 8.3 requirements.... and this is quite hard. And
since our gforge has been modified since 2005, not it's very difficult
to revert our changes to gforge 4.7 trunk... so it's probably we will
stay in 8.1 or 8.2 waiting for a future migration to Gforge AS (5).

-----Original Message-----
From: Ricardo Mercado Araneda <rmercado(at)dportales(dot)cl>
To: pgsql-admin(at)postgresql(dot)org
Subject: [ADMIN] Sobre Actualizacion
Date: Wed, 10 Jun 2009 17:16:39 -0400

Estimados:
Tengo instalado Postgresql 7.4.8 y quisiera migrar a postgres 8.x.

Mi pregunta es si hay alguna pauta para hacerlo. Solo se que puedo tener
problemas con la perdida de datos. Necesito me orientes por favor

Ricardo Mercado Araneda.