| From: | Gary Doades <gpd(at)gpdnet(dot)co(dot)uk> | 
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> | 
| Cc: | pgsql-performance(at)postgresql(dot)org | 
| Subject: | Re: Strange Create Index behaviour | 
| Date: | 2006-02-15 21:34:11 | 
| Message-ID: | 43F39E53.1020009@gpdnet.co.uk | 
| Views: | Whole Thread | Raw Message | Download mbox | Resend email | 
| Thread: | |
| Lists: | pgsql-hackers pgsql-performance | 
Tom Lane wrote:
  > I tried forcing PG to use src/port/qsort.c on the Fedora machine,
> and lo and behold:
> 	new Fedora 4 machine: shortest 434 msec, longest 8530 msec
> 
> So it sure looks like this script does expose a problem on BSD-derived
> qsorts.  Curiously, the case that's much the worst for me is the third
> in the script, while the shortest time is the first case, which was slow
> for Gary.  So I'd venture that the *BSD code has been tweaked somewhere
> along the way, in a manner that moves the problem around without really
> fixing it.  (Anyone want to compare the actual FreeBSD source to what
> we have?)
> 
If I run the script again, it is not always the first case that is slow, 
it varies from run to run, which is why I repeated it quite a few times 
for the test.
Interestingly, if I don't delete the table after a run, but just drop 
and re-create the index repeatedly it stays a pretty consistent time, 
either repeatedly good or repeatedly bad!
Regards,
Gary.
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Gary Doades | 2006-02-15 21:47:46 | Re: Strange Create Index behaviour | 
| Previous Message | Tom Lane | 2006-02-15 21:27:54 | Re: Strange Create Index behaviour | 
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2006-02-15 21:36:51 | Re: Postgres slower than MS ACCESS | 
| Previous Message | Jay Greenfield | 2006-02-15 21:29:51 | Re: Postgres slower than MS ACCESS |