Re: So, is COUNT(*) fast now?

Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I had wondered whether it'd be worth optimizing that along the
> lines of slot_getallattrs().  But most indexes probably have only
> one column, or anyway not enough to make for a useful savings.
From a heavily-used production database:
cir=> select indnatts, count(*) from pg_index group by indnatts
order by indnatts;indnatts | count 
----------+-------       1 |   200       2 |   684       3 |   155       4 |    76       5 |    43       6 |    13
7 |     2       9 |     1
 
(8 rows)
This includes system table and TOAST table indexes (which seem to
have two columns).  There are over 400 user tables, each of which
has a primary key, so most primary keys in our database are more
than one column.
-Kevin