Firebird 1.5.3 X Postgresql 8.1.3 (linux and windows)

Hello,
The performance comparison saga of the last month continues (see list archive).
After some time experimenting on windows, the conclusion is clear:

windows is likely crap for databases other than MS-SQL.

I guess that MS-SQL uses lot of undocumented api calls, may run in kernel
mode, ring 0 and a lot of dirty tricks to get some reasonable performance.

Then, I asked my coleague to send a new FB dump and a Pg dump to try at my
desktop machine.
This time, the database is somewhat bigger. Around 20 million records.

The timings are attached. Tried to follow the same query sequence on both files.
Both databases are much more faster on linux than on windows, and the desktop
machine is not dedicated and tuned. (no scsi, no raid, many services enabled,
ext3 fs, etc).
At many of the queries, postgresql is faster, sometimes way MUCH faster.
But Firebird have very good defaults out of the box and a few of the queries
are really a pain in Postgresql.
Please, see the abismal timing differences at the last 2 queries, for example.
They used 100% cpu, almost no disk activity, no twait cpu, for loooong time to
complete.
Maybe these queries bring into the light some instructions weaknesses, or bad
tuning.
Do you have some suggestions?
Regards.

Andre Felipe Machado
http://www.techforce.com.br
linux blog