On Fri, Mar 28, 2008 at 05:34:30PM +0000, Gregory Stark wrote: > But what I really need is someone to read the patch and say "looks good" or > point out things they don't like. In particular, what I really, really want is > some guidance on the singular key question I asked.
I was going to write all sorts of stuff, till I noticed Heikki said basically everything I was going to say: - I think normal index scans could benefit from this (it was measurable when I was playing with AIO in postgres a few years back). - The integration with the bitmap scan is good, neat even - I think the number of preread_count is far too small, given you get a benefit even if you only have one spindle. - I don't understand the ramp-up method either. People spend a lot of time worrying about hundreds of posix_fadvise() calls but you don't need anywhere near that much to be effective. With AIO I limited the number of outstanding requests to a dozen and it was still useful. You lose nothing by capping the number of requests at any point. > I want to know if we're interested in the more invasive patch restructuring > the buffer manager. My feeling is that we probably are eventually. But I > wonder if people wouldn't feel more comfortable taking baby steps at first > which will have less impact in cases where it's not being heavily used. I think the way it is now is neat and simple and enough for now. Have a nice day, -- Martijn van Oosterhout <[EMAIL PROTECTED]> http://svana.org/kleptog/ > Please line up in a tree and maintain the heap invariant while > boarding. Thank you for flying nlogn airlines.
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