Re: PostgresSQL vs. Informix

On Nov 28, 2007 9:32 AM, Chad Hendren <Chad(dot)Hendren(at)sun(dot)com> wrote:
> I have a large OEM customer (one of the top 8 for Sun worldwide) that is
> considering embedding PostgreSQL into the core of their primary product
> instead of Informix. He is trying to build his case for this change.
> Do we have anything that I can forward to him (something like the
> presentation you did at CEC?) to help him build his case?

I can't offer much in the way of a case study, but I am an Informix
customer that has been doing an informal feasibility study on
switching to PostgreSQL. I've learned a ton from the high quality PG
docs and from the PG mailing lists.

Both have their pros and cons. I haven't had equal hardware to compare
PG performance, but my impression is that it is Informix is faster and
has a more robust query planner. And by that, I mean that the Informix
planner does a great job without things like data type casts and other
help from the SQL developer. If I had to put a number on it, I would
say that PG is 75 to 80% as fast as Informix. Please, don't anyone
start a flame war over this, I'm just guessing here. With equal
hardware and some more tuning, I'm sure I could do better with PG.

Another edge for Informix is the fully synchronous replication feature
where a committed transaction on the primary is guaranteed to be
committed to disk on the secondary if you configure things
appropriately. High availability is critical for us and that's been a
weak spot for PG as far as I'm concerned. Yes, PG has replication,
but in my opinion, it's not 'enterprise' class just yet.

Lastly on the Informix side, they have more advanced online
backup/restore tools. It's similar to PG PITR backup but does not
depend on file-system level backup tools. The option I use (called
ontape) stores data in a proprietary format to disk or tape. It also
has an incremental backup option so you don't have to do a full dump
every time. There is a more advanced Informix backup tool called
onbar, but I haven't worked with it enough to comment on it.

What does PG have going for it? Price, obviously. I'd love to have
that $100k that I just spent back. PG has better conformance to SQL
language standards, so portability of code would be easier. PG has
some better built in functions and indexing features. I prefer the
PLPGSQL language for stored procedures to Informix.PG has more options
for stored procedure languages (python, perl). PG has table
inheritance, Informix does not.

One of the most impressive things about PG has been these mailing
lists. Informix support is OK, but the front-line support drones just
don't have the same access to developers who really know what's going
on that you can get directly on this list. Heck, PG developers have
answered my questions here on the weekend! I don't know if you can
even put a price on such direct access to high-level gurus.

I wish I had a better feature comparison list for you. I'm sure I've
failed to mention a lot of great things about PG here, but like I
said, my evaluation has been pretty informal. However at this time, I
have concluded that we could move our company from Informix to PG
without having to give up too much, other than the big licensing fees.
We use a lot of open source software at our company and I would love
to add PostgreSQL to the list.

Jeff