Nice! - Luke
On 1/30/08 9:22 AM, "Gregory Stark" <[EMAIL PROTECTED]> wrote: > > Here's the WIP patch for doing prereading when doing bitmap index scans. > > I was performance testing it as I was developing it here: > > http://archives.postgresql.org/pgsql-hackers/2007-12/msg00395.php > > Note that this only kicks in for bitmap index scans which are kind of tricky > to generate. I used the attached function to generate them in the post above. > > Also note I wouldn't expect to see much benefit unless you're on a raid array, > even a small one. But if you are on a raid array then the benefit should be > immediately obvious or else posix_fadvise just isn't working for you. I would > be interested in hearing on which OSes it does or doesn't work. > > *If* this is the approach we want to take rather than restructure the buffer > manager to avoid taking two trips by marking the buffer i/o-in-progress and > saving the pinned buffer in the bitmap heap scan then this is more or less in > final form. Aside from some autoconf tests and the documentation for the GUC I > think it's all in there. > > ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
