Re: Help with unpredictable use of indexes on large tables... - Mailing list pgsql-general

Tom Lane wrote:

> Also I'd suggest trying
>
>     select year from [table] group by year
>
> which is capable of using a hash aggregation approach; that will likely
> beat either of these plans.

Just out of curiosity, why doesn't the planner consider the same plan
for the OP's original query:

   select distinct year from [table]

Aren't these equivalent (except for the order)?

Thanks.

- John Burger