am Thu, dem 06.03.2008, um 11:13:01 +0530 mailte sathiya psql folgendes: > count(*) tooks much time... > > but with the where clause we can make this to use indexing,... what where > clause we can use?? An index without a WHERE can't help to avoid a seq. scan. > > Am using postgres 7.4 in Debian OS with 1 GB RAM, PG 7.4 are very old... Recent versions are MUCH faster. > > am having a table with nearly 50 lakh records, > > it has more than 15 columns, i want to count how many records are there, it is > taking nearly 17 seconds to do that... > > i know that to get a approximate count we can use > SELECT reltuples FROM pg_class where relname = TABLENAME; > > but this give approximate count, and i require exact count... There aren't a general solution. If you realy need the exact count of tuples than you can play with a TRIGGER and increase/decrease the tuple-count for this table in an extra table. Andreas -- Andreas Kretschmer Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header) GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://mail.postgresql.org/mj/mj_wwwusr?domain=postgresql.org&extra=pgsql-performance
