Re: [GENERAL] Help with unpredictable use of indexes on large tables...

[John D. Burger]

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


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