Re: Migrating from Informix to Postgre

Dinesh Anchan wrote:
> Thank you for your response.
>
> I understand that it is not heterogenous. Is it open?
>
> Let's say, I am running a transaction in Informix and part of that
> transaction has to update another database which is running on Postgre. Is
> this possible? Informix claims that it supports heterogenous transactions
> as long as other participating database servers are capable of doing so.
>
> We were thinking of replacing servers one at a time.

No, we don't support anything like that. We do support crossdb/server
query execution, but those queries are separate events, not rolled back
if the transaction aborts.

>
> Thank you for your advice.
>
> D
>
> -----Original Message-----
> From: Bruce Momjian [mailto:pgman(at)candle(dot)pha(dot)pa(dot)us]
> Sent: Friday, October 18, 2002 11:51 AM
> To: Dinesh Anchan
> Cc: pgsql-general(at)postgresql(dot)org
> Subject: Re: [GENERAL] 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.
>
> --
> Bruce Momjian | http://candle.pha.pa.us
> pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
> + If your life is a hard drive, | 13 Roberts Road
> + Christ can be your backup. | Newtown Square, Pennsylvania 19073
>
>

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073