Hannu, On 10/3/05 2:43 PM, "Hannu Krosing" <[EMAIL PROTECTED]> wrote:
> Just FYI, I run a count(*) on a 15.6GB table on a lightly loaded db and > it run in 163 sec. (Dual opteron 2.6GHz, 6GB RAM, 6 x 74GB 15k disks in > RAID10, reiserfs). A little less than 100MB sec. This confirms our findings - sequential scan is CPU limited at about 120MB/s per single threaded executor. This is too slow for fast file systems like we're discussing here. Bizgres MPP gets 250MB/s by running multiple scanners, but we still chew up unnecessary amounts of CPU. > After this I ran count(*) over a 2.4GB file from another tablespace on > another device (4x142GB 10k disks in RAID10) and it run 22.5 sec on > first run and 12.5 on second. You're getting caching effects here. - Luke ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
