Re: Postgresql and multithreading

On Wed, 2002-10-16 at 23:08, Curtis Faith wrote:
> Bruce Momjian wrote:
> I tried to prepare as best I could before bringing anything forward to
> HACKERS. In particular, I read the last two years of archives with anything
> to do with the WAL log and looked at the current code, read the TODOs, read
> a fair amount of discussions about aio. etc. So I was attempting to comply
> with my interpretation of the process. Yet, despite these efforts, you no
> doubt consider me guilty of creating unnecessary work, an outcome neither
> of us desired.

But that "unneccessary work" resulted in Tom finding and fixing an
unintended behaviour (aka a performance bug) that prevented postgres
from ever doing more than 1 commit per disk revolution on non-lieing
SCSI disks ;)

> I'm undeterred in my desire to come up with something meaningful and am
> working on some interesting tests. I do, however, now know that the level
> of scepticism and the standards of architectural purity are high. I
> consider this good all around.

I still have big expectations for use of aio, especially considering
that at least for free OSes one is not forced to stop at the DB/OS
boundary, but are free to go and improve the os side implementation as
well if it is needed.

But still some empirical tests are probably needed - if we can keep IO
occupied for 99% in a meaningful way withou aio, then the time is
probably better spent on something else ;)

--------------------
Hannu