On Sun, 12 Apr 1998, Matthew N. Dodd wrote:
> On Sun, 12 Apr 1998, The Hermit Hacker wrote:
> > I hate to have to ask, but how is MMAP or AIO better then sfio? I
> > haven't had enough time to research any of this, and am just starting to
> > look at it...
>
> If its simple to compile and works as a drop in replacement AND is faster,
> I see no reason why PostgreSQL shouldn't try to link with it.
That didn't really answer the question :(
> Keep in mind though that in order to use MMAP or AIO you'd be
> restructuring the code to be more efficient rather than doing more of the
> same old thing but optimized.
I don't know anything about AIO, so if you can give me a pointer
to where I can read up on it, please do...
...but, with MMAP, unless I'm mistaken, you'd essentially be
reading the file(s) into memory and then manipulating the file(s) there.
Which means one helluva large amount of RAM being required...no?
Using stdio vs sfio, to read a 1.2million line file, the time to
complete goes from 7sec to 5sec ... that makes for a substantial savings
in time, if its applicable.
the problem, as I see it right now, is the docs for it suck ...
so, right now, I'm fumbling through figuring it all out :)
Marc G. Fournier
Systems Administrator @ hub.org
primary: scrappy@hub.org secondary: scrappy@{freebsd|postgresql}.org