On Thu, Mar 6, 2008 at 5:08 PM, A. Kretschmer <
andreas.kretschmer@schollglas.com> wrote:>
> 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.
Or do something like:
ANALYZE tablename;
select reltuple from pg_class where relname = 'tablename';
That will also return the total number of rows in a table and I guess might be much faster then doing a count(*) but yes if trigger can be an option that can be the easiest way to do it and fastest too.
--
Shoaib Mir
Fujitsu Australia Software Technology
shoaibm[@]fast.fujitsu.com.au