On Mon, Nov 24, 2008 at 10:26 AM, Andrus <kobruleht2@xxxxxx> wrote: >> it was veery fast. To be honest I do not know what is happening?! > > This is really weird. > It seems that PostgreSql OFFSET / LIMIT are not optimized and thus typical > paging queries And how exactly should it be optimized? If a query is even moderately interesting, with a few joins and a where clause, postgresql HAS to create the rows that come before your offset in order to assure that it's giving you the right rows. > SELECT ... FROM bigtable ORDER BY intprimarykey OFFSET pageno*100 LIMIT 100 This will get progressively slower as pageno goes up. > SELECT ... FROM bigtable ORDER BY intprimarykey OFFSET 0 LIMIT 100 That should be plenty fast. > cannot be used in PostgreSql at all for big tables. Can't be used in any real database with any real complexity to its query either. > Do you have any idea how to fix this ? A standard workaround is to use some kind of sequential, or nearly so, id field, and then use between on that field. select * from table where idfield between x and x+100; -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
