Re: Read/Write block sizes
От | Ron |
---|---|
Тема | Re: Read/Write block sizes |
Дата | |
Msg-id | 6.2.3.4.0.20050825185441.05e63ef0@pop.earthlink.net обсуждение исходный текст |
Ответ на | Re: Read/Write block sizes (Chris Browne <cbbrowne@acm.org>) |
Список | pgsql-performance |
At 04:49 PM 8/25/2005, Chris Browne wrote: >rjpeace@earthlink.net (Ron) writes: > > At 03:45 PM 8/25/2005, Josh Berkus wrote: > >> > Ask me sometime about my replacement for GNU sort. Â It uses the > >> > same sorting algorithm, but it's an order of magnitude faster due > >> > to better I/O strategy. Â Someday, in my infinite spare time, I > >> > hope to demonstrate that kind of improvement with a patch to pg. > >> > >>Since we desperately need some improvements in sort performance, I > >>do hope you follow up on this. > > > > I'll generalize that. IMO we desperately need any and all > > improvements in IO performance. Even more so than we need > > improvements in sorting or sorting IO performance. > >That's frankly a step backwards. Feel free to "specialise" that instead. We can agree to disagree, I'm cool with that. I'm well aware that a Systems Approach to SW Architecture is not always popular in the Open Source world. Nonetheless, my POV is that if we want to be taken seriously and beat "the big boys", we have to do everything smarter and faster, as well as cheaper, than they do. You are not likely to be able to do that consistently without using some of the "icky" stuff one is required to study as part of formal training in the Comp Sci and SW Engineering fields. >A patch that improves some specific aspect of >performance is a thousand times better than any >sort of "desperate desire for any and >all improvements in I/O performance." minor twisting of my words: substituting "desire" for "need". The need is provable. Just put "the big 5" (SQL Server, Oracle, DB2, mySQL, and PostgreSQL) into some realistic benches to see that. Major twisting of my words: the apparent implication by you that I don't appreciate improvements in the IO behavior of specific things like sorting as much as I'd appreciate more "general" IO performance improvements. Performance optimization is best done as an iterative improvement process that starts with measuring where the need is greatest, then improving that greatest need by the most you can, then repeating the whole cycle. _Every_ improvement in such a process is a specific improvement, even if the improvement is a decision to re-architect the entire product to solve the current biggest issue. Improving sorting IO is cool. OTOH, if pg's biggest IO problems are elsewhere, then the amount of overall benefit we will get from improving sorting IO is going to be minimized until we improve the bigger problem(s). Amdahl's Law. >The "specialized patch" is also pointedly better >in that a *confidently submitted* patch is >likely to be way better than any sort of >"desperate clutching at whatever may come to hand." Another distortion of my statement and POV. I never suggested nor implied any sort of "desperate clutching...". We have _measurable_ IO issues that need to be addressed in order for pg to be a better competitor in the marketplace. Just as we do with sorting performance. >Far too often, I see people trying to address >performance problems via the "desperate >clutching at whatever seems near to hand," and that >generally turns out very badly as a particular >result of the whole "desperate clutching" part. > >If you can get a sort improvement submitted, that's a concrete improvement... As I said, I'm all in favor of concrete, measurable improvement. I do not think I ever stated I was in favor of anything else. You evidently are mildly ranting because you've seen some examples of poor SW Engineering Discipline/Practice by people with perhaps inadequate skills for the issues they were trying to address. We all have. "90% of everything is Jreck (eg of too low a quality)." OTOH, I do not think I've given you any reason to think I lack such Clue, nor do I think my post was advocating such thrashing. My post was intended to say that we need an Overall Systems Approach to pg optimization rather than just applying what compiler writer's call "peephole optimizations" to pg. No more, no less. I apologize if I somehow misled you, Ron Peacetree
В списке pgsql-performance по дате отправления: