As part of my ongoing evaluation of PostgreSQL I have been doing a little stress testing. I though I would share an interesting result here..
Machine spec: 500 MHz PIII 256MB RAM "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 rowcount. 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 14th 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? Cheers, Gary. ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
