Good news,
I partially fixed the problem on Linux 2.4. It appears the responsiveness can be improved significantly by tuning the disk IO elevator in Linux using "elvtune" in util-linux. The elevator in Linux is used to re-order read/write requests to reduce disk seeks by ordering requests according to disk sectors. Unfortunately, the elevator in kernel 2.4 is not very smart (or flexible I should say depending on your needs) and can starve a read/write request for a long time if not properly tuned. elvtune -r 2048 -w 8192 /dev/hdc (default Redhat 9): ====================================================
Are you sure ? In my RH9.0 installation I obtain:
# elvtune /dev/sda7
/dev/sda7 elevator ID 5 read_latency: 64 write_latency: 8192 max_bomb_segments: 6
may be your problem is due the fact that someone change these values on your machine!
Regards Gaetano Mendola
---------------------------(end of broadcast)--------------------------- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match