On Tue, Sep 9, 2008 at 2:07 PM, Andrew Sullivan <ajs@xxxxxxxxxxxxxxxxx> wrote: > > . . . your figuring here is indeed simplistic. Every day I see > requests for help from people who have followed the rule of thumb "1/4 > of memory for shared_buffers", except that they're also running > apache+jakarta, MySQL, and a mail server on the same box. They wonder > why the stock advice is so wrong. It's wrong because a > general-purpose tool is almost never going to come pre-set for every > possible workload you might want to throw at it. So even "how much > memory" there is on the machine is a question that is harder to answer > than it might seem. Disk layout, data access patterns, even the > filesystem you choose can make significant differences in how the > system performs. Just as common is the beginner showing up with an 8 core opteron server with 64 Gigs of ram trying to get fast write transactions on a single 7200 rpm 500G sata drive. > Finally, part of the reason people make these claims is because they > tend to hold Postgres up against toy systems that are _not_ designed > to scale up. A certain well known database product, for instance, has > been struggling for the last several years to turn itself into a > full-featured, high-volume, safe transactional system. But the seams > keep showing, because it just wasn't designed for this workload in the > first place. But it sure is fast out of the box on a single-user > system! reference tweakers.net http://tweakers.net/reviews/649/8/database-test-sun-ultrasparc-t1-vs-punt-amd-opteron-pagina-8.html http://tweakers.net/reviews/661/6/database-test-intel-xeon-clovertown-x5355-pagina-6.html
