"Trevor Talbot" wrote: >On 8/16/07, Rainer Bauer <usenet@xxxxxxxxxx> wrote: > >> My point is that whatever search criterias are involved and how many items are found eBay always returns the *accurate* number of items found. >> >> Before this drifts off: >> * I do know *why* count(*) is slow using Postgres. >> * I *think* that count(*) is fast on eBay because count is cheaper using Oracle (which eBay does: <http://www.sun.com/customers/index.xml?c=ebay.xml>). >> * I realize that pagination for multi-million tuple results does not make sense. > >You got me curious, so I went hunting for more hints on what eBay >actually does, and found these slides from a presentation given by two >eBay engineers last year: >http://www.addsimplicity.com/downloads/eBaySDForum2006-11-29.pdf Quite interesting. >It's, er, a whole different ballgame there. Database behavior is >barely involved in their searching; they do joins and RI across >database clusters within the _application_. I knew eBay was big, but >wow... Well then: forget the Oracle count(*) argument :-( Rainer ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
