Hello, I'm using PostgreSQL 7.4.2 (package from backports.org) on a Debian (woody) box. The machine is IBM eServer 345 with two 2.8 Xeon CPUs, it has 1024MB of RAM and two 15k RPM SCSI disks running in hardware RAID1, which is provided by the onboard LSI Logic controller (LSI53C1030).
The database consists of two rather large tables (currently about 15 million rows in one table and about 5 million in the other one). Both tables have 5 indexes (4 btree/1 hash). Application running on the server INSERTs a lot of stuff to the tables (which is not the target use of the DB, it'll add data periodically, about 300 rows per 10 minutes). Queries (SELECTs) run perfectly fine on the database, thanks to the indexes we have here probably. Performance issue, I'm experiencing here, is somewhat weird - server gets high average load (from 5 up to 15, 8 on average). Standard performance monitoring utilities (like top) show that CPUs are not loaded (below 20%, often near zero). With kernel 2.6.x which I was using earlier, top showed very high "wa" values (which indicate I/O waiting, AFAIK). I've googled some issues with 2.6 kernels and LSI Logic controllers running RAID, so I've downgraded the kernel to 2.4.26. The machine started to behave a bit better, but still high load states look weird. Unfortunately, top with 2.4 kernels does not show "wa" column, so I can't be sure if the load is caused by waiting for disks, but high idle values and high average load would suggest it. With kernel 2.6 swap was almost always 100% free, with 2.4.26 Linux eats below 5 megabytes of swapspace. PostgreSQL is running with shared_mem set to 48000, sort_mem = 4096, fsync off. Whole config is available here: http://ludojad.itpp.pl/~eleven/pg-high-load.conf I've also made some iostat report (using iostat 3 1000 as suggested in one of the posts): http://ludojad.itpp.pl/~eleven/iostat.log Any solutions I should consider? I'd be grateful getting some hints on this. -- 11. ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend