Lazlo, > Meanwhile, "iostat 5" gives something like this: > > tin tout KB/t tps MB/s KB/t tps MB/s us ni sy in id > 1 14 128.00 1 0.10 128.00 1 0.10 5 0 94 1 0 > 0 12 123.98 104 12.56 123.74 104 12.56 8 0 90 2 0 This is your problem. Do the following and report the results here: Take the number of GB of memory you have (say 2 for 2GB), multiply it by 250000. This is the number of 8KB pages you can fit in twice your ram. Let's say you have 2GB - the result is 500,000. Use that number to do the following test on your database directory: time bash -c "dd if=/dev/zero of=/<dbdir>/bigfile bs=8k count=<number_from_above> && sync" Then do this: time bash -c "dd if=/<dbdir>/bigfile of=/dev/null bs=8k" > > I made another test. I create a file with the identifiers and > names of the products: > > psql#\o products.txt > psql#select id,name from product; > > Then I can search using grep: > > grep "Mug" products.txt | cut -f1 -d\| > > There is a huge difference. This command runs within 0.5 > seconds. That is, at least 76 times faster than the seq scan. The file probably fits in the I/O cache. Your disks will at most go between 60-80MB/s, or from 5-7 times faster than what you see now. RAID 1 with one query will only deliver one disk worth of bandwidth. - Luke
