Re: Why is PostgreSQL 9.1 not using index for simple equality select

Yang Zhang <yanghatespam@gmail.com> writes:
>     db=> explain select * from lead where email = 'blah';
>                              QUERY PLAN
>     ------------------------------------------------------------
>      Seq Scan on lead  (cost=0.00..319599.38 rows=1 width=5108)
>        Filter: (email = 'blah'::text)
>     (2 rows)

That's awfully odd.  What data type is the "email" column?

It seems possible also that the index on it is marked invalid.  I'd have
expected \d to tell you so, but maybe you're using a version of psql that
doesn't know about that.  It'd be interesting to look at
select * from pg_index where indexrelid = 'index name here'::regclass;


            regards, tom lane