On Fri, May 19, 2006 at 09:29:44PM +0200, Martijn van Oosterhout wrote: > On Fri, May 19, 2006 at 10:02:50PM +0300, Hannu Krosing wrote: > > > > It's just SELECT count(*) FROM (SELECT * FROM accounts ORDER BY bid) a; > > > > If the tape routines were actually storing visibility information, I'd > > > > expect that to be pretty compressible in this case since all the tuples > > > > were presumably created in a single transaction by pgbench. > > > > Was he not using pg_bench data ? > > Hmm, so there was only 3 integer fields and one varlena structure which > was always empty. This prepended with a tuple header with mostly blank > fields or at least repeated, yes, I can see how we might get a 25-to-1 > compression. > > Maybe we need to change pgbench so that it puts random text in the > filler field, that would at least put some strain on the compression > algorithm...
Wow, I thought there was actually something in there... True random data wouldn't be such a great test either; what would probably be best is a set of random words, since in real life you're unlikely to have truely random data. -- Jim C. Nasby, Sr. Engineering Consultant [EMAIL PROTECTED] Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461 ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
