Extracted from debian-list
Tip provided by Kevin Cheek

See http://www.tcx.se/benchmark.html for some interesting benchmarks
comparing several common db systems including oracle, ms-sql, pgsql,
and others.

For a pretty comprehensive comparison of database system limitations
and capabilities, see http://www.tcx.se/crash-me-choose.htmy

I use MySQL for my work and am extremely happy with it. It is
extrememly reliable and extremely fast. It is significantly faster
than pgsql and in my experience, it is also much more reliable (I used
pgsql before I switched to MySQL). MySQL doesn't support some of
Oracle's features like transactions, views, etc, but since I don't
need them, I can benefit from the much smaller and faster MySQL
system.

MySQL has no problems dealing with large sets of data and large
BLOBS. I have one MySQL db that contains over 3.5GB of data. In that
db, two of the tables are over 1.5GB (they contain mostly TIFF
images). Performance is great even with those relatively large table
sizes.

Does anyone have a feel for the relative performance of the various
SQL databases in Debian ? I'd also be interested to know how these
compare to something like Oracle (under either NT or Linux).

I'm looking to manage two databases: one of roughly ten thousand
records a few k in size, the other 100,000 rather smaller records. It
might well be feasible to use something like gdbm for the latter one.

Postgresql runs like greased lightning.  In some tests involving
0.5 million records of a few K in size, it blew away MS SQL Server.
I think it was version 6.  Postgresql runs well, although it does have
some limitations.  ODBC was the main weakness I noticed.  We're currently
deploying Oracle on a Debian server...

Oracle is bloatware even by Microsoft standards.  I can't comment on
speed yet.