am Fri, dem 20.04.2007, um 12:03:44 +0100 mailte Richard Huxton folgendes: > A. Kretschmer wrote: > >in a SELECT with a condition 'WHERE foo IN (1,2,3,4,...)' with a large > ... > >But if the list increase the planner choose an seq-scan. The amount of > >values in the list is about 200 and the table has about 250.000 rows. > > > >How can we avoid the seq-scan? > > Are you sure you'd want to? What plan have you found to be faster with > 200 tests?
It's not my problem - i found it in a forum (german) http://pg-forum.de/showthread.php?t=1332 If the list contains up to 195 entrys -> up to 195 bitmap index scans and BitmapOr -> 7.839ms If the list contains 196 entrys -> seq-scan -> 5591.567ms Andreas -- Andreas Kretschmer Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header) GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
