David Link <dlink@soundscan.com> writes:
> tiger=# explain select * from bk_inv where isbn = 'foo';
> NOTICE: QUERY PLAN:
> Index Scan using bk_inv_isbn_idx on bk_inv (cost=0.00..53.13
> rows=13 width=48)
> However, however using the store index costs are still rather high -
> why is that!!??
> tiger=# explain select * from bk_inv where store = 'foo';
> NOTICE: QUERY PLAN:
> Index Scan using bk_inv_store_idx on bk_inv (cost=0.00..53456.09
> rows=13488 width=48)
Note the difference in estimated number of rows retrieved; that's where
the cost difference comes from. You may care to read
http://www.ca.postgresql.org/users-lounge/docs/7.1/postgres/performance-tips.html
regards, tom lane
