As part of my ongoing evaluation of PostgreSQL I have been doing a little stress 
I though I would share an interesting result here..

Machine spec:
500 MHz PIII
"old-ish" IDE HD (5400RPM)
Linux 2.4.22 kernel (Madrake 9.2)

I have PostgreSQL 7.4.1 installed and have managed to load up a 1.4 GB database 
from MS SQLServer. Vaccum analyzed it.

As a test in PosgreSQL I issued a statement to update a single column of a table 
containing 2.8 million rows with the values of a column in a table with similar 
Using the above spec I had to stop the server after 17 hours. The poor thing was 
thrashing the hard disk and doing more swapping than useful work.

Having obtained a copy of Mandrake 10.0 with the 2.6 kernal I though I would give it a 
go. Same hardware. Same setup. Same database loaded up. Same postgresql.conf file 
to make sure all the settings were the same.  Vaccum analyzed it.

same update statement COMPLETED in 2 hours 50 minutes. I'm impressed.

I could see from vmstat that the system was achieving much greater IO thoughput than 
the 2.4 kernel. Although the system was still swapping there seems to be a completely 
different memory management pattern that suits PostgreSQL very well.

Just to see that this wasn't a coincidence I am repeating the test. It is now into the 
hour using the old 2.4 kernel. I'm going to give up.....

Has anyone else done any comparative testing with the 2.6 kernel?


---------------------------(end of broadcast)---------------------------
TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]

Reply via email to