Re: Migrating from Informix to Postgre

Dinesh Anchan wrote:
> Hi Everyone,
>
> I am a first timer in this forum.
>
> We are currently using Informix and looking for a more economic database
> solution(combination of Linux and Opensource database).  We currently have 5
> database servers; 1 running on Sun E450(4 cpu), 2 on Sun E420(4 cpu), 1 on
> Sun E250 and 1 on Netra T1, with database sizes 30 GB, 12 GB, 12GB, 15GB,
> 2GB respectively.  Databases on E420s are replicated between them.  There
> are at least 10 tables which hold more than 75 million records and
> fragmented accross different tablespaces. They have indexes and used
> extensively in DSS type and as well as OLTP type of queries.
>
> I went through lot of material in the discussion group but could not find a
> straight forward answer for the following questions.  I would greatly
> appreciate if someone can share your experience with Postgre.
>
> 1. How comfortably Postgre can support these databases( with respect to
> volume)?

No problem.  We have Oracle/Informix folks migrating all the time.

> 2. How reliable and what kind of replication Postgre provides? Is it log
> based or transaction based?

Only single-master replication available in /contrib/rserv and
/contrib/dbmirror.  We are working on multi-master for a later release.

We also don't have point-in-time recovery yet, but that will be in 7.4,
due out in about 6 months.

> 3. Does it support table fragmentation accross multiple tablespaces?

No.

> 4. Does it support raw devices?

No.  We feel the performance improvement on raw devices is minimal.

> 5. I have read that it is transactional. But is it heterogeneous?  Can I
> update multiple databases in multiple database servers of different family
> (like informix, MySQL etc) in a single transaction?

You can only update one database per session connection.  We do have
schemas in 7,3, though.  We are in 7.3 beta now.

> 6. How is the performance?

Very similary to Informix/Oracle;  faster for some things, slower for
others.

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