On Tue, Jun 13, 2006 at 03:21:34PM -0700, Mischa Sandberg wrote: > Jim C. Nasby wrote: > ... > >Actually, in 8.1.x I've seen some big wins from greatly increasing the > >amount of shared_buffers, even as high as 50% of memory, thanks to the > >changes made to the buffer management code. ... > > Anyone else run into a gotcha that one of our customers ran into? > PG 7.4.8 running on Solaris 2.6, USparc w 4GB RAM. > Usually about 50 active backends. > (No reason to believe this wouldn't apply to 8.x). > > Initially shared_buffers were set to 1000 (8MB). > Then, we moved all apps but the database server off the box. > > Raised shared_buffers to 2000 (16MB). > Modest improvement in some frequent repeated queries. > > Raised shared_buffers to 16000 (128MB). > DB server dropped to a CRAWL. > > vmstat showed that it was swapping like crazy. > Dropped shared_buffers back down again. > Swapping stopped. What's sort_mem set to? I suspect you simply ran the machine out of memory. Also, Solaris by default will only use a portion of memory for filesystem caching, which will kill PostgreSQL performance. -- Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
