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
