"PostgreSQL Bugs List" <pgsql-bugs@postgresql.org> writes:
> When I do a select * from table limit 1
> Postgresql does a sequential scan on the whole table.
AFAICS you simply are misreading the EXPLAIN output.
(It also sounds like you haven't vacuumed or analyzed that table in a
mighty long time... if you're having performance problems that is
probably the reason...)
regards, tom lane