Re: MySQL or Postgres ?

Fabiàn R. Breschi <fabian.breschi@acm.org> wrote in message news:<3D48185C.B6663ED7@acm.org>...
> Hi there,
>
> If you'd have to suggest which type of database one migh use, how would
> you reflect the differences between them to show up pros and cons ?

Some thoughts I posted last night to another group under basically same subject:

MySQL has pretty robust replication and multiple ways to handle
backups. Actually you now got hotbackup for MySQL if you run on innodb
tables (www.innodb.com), which you probably should, as it offers
transactions, row-level locking and rough foreign key implementation.
Hotbackup means that you can backup your live database on the fly.

AFAIK, Postgre don't have replication. Great Bridge gang was doing
something but it never happend I think.

For basic backups both of them should be fine. Note that with Postgre,
if you get lot's of updates you have to run vacuum to clean up the
transaction mess, and this basically halts the db.

On some situations MySQL is slower, like some multi-join
queries and particularly when running on MyISAM tables, in situations when
select's and updates are coming in on a same table in a steady flow.
This is because MyISAM handles locking on a _table_ level, which is
not that nice and makes MySQL not so scalable on those situations. Now
again if you instead use Inno tables you have no problems because of
the row locking.

Personally, I have not used Postgre in really high-traffic situations,
but on some situations it simply is better because of it's feature
set. Data integrity specifically being one of them. In many cases the
most important thing is INTEGRITY on a server level. Performance comes
next. And no matter what some MySQL idealists say; in some cases you
simply cannot impliment integrity checks on a client-level (like
making your client do say, foreign key checks). What if you have many
different type of client applications modifying the same data? What if
you have to use some GUI client where nothing can be implimented? Whatever.
Besides, that's inheritently wrong thinking anyways.

It all boils down what is important to _you_. Most of the database
implementations are unique so making comparisons is pointless. Do you
need foreign keys? Do you need sub-selects? No? Stored procedures? Do
you need speed on bulk inserts? Speed on certain select's? If you are
running website and clients are doing the same queries most of the
time, then maybe query cache might help?

Bottom line:
MySQL
- Fast & reliable - has proven this in real-world situations
- Capable of handling big tables efficiently. And this is so no matter
what  some whiners say. I've seen 200G _single_ table. Many
warehousers running with 10(ns) of gig tables without any problems
- Lacking many major features: stored procs, foreign keys,
sub-selects...
- Some neat features like: fulltext indexing, replication, query
cache..
- Library version of the server! You can actually link it inside your
app (no admin worries, no client-server overhead).

Postgre
- Tons of features
- Even more features
- And then some...
- Seems to be stable and scale nicely
- More that Oracle like industry db feeling :)
- If you want to extend / modify the server code, it's very well
commented = easy to read :)
- No replication, no fulltext index, no query cache

Hopefully this is for any help!

Best,
Antti Halonen          # Tietokanta & Tietoverkko Konsultointia
Exadata              # Database & Network Consulting
                                  http://www.exadata.fi