Re: Multi-column distinctness.

On Tue, Oct 20, 2015 at 11:59 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> On Tue, Oct 20, 2015 at 10:51 AM, Tomas Vondra
>> <tomas.vondra@2ndquadrant.com> wrote:
>>>>> ISTM that we could use COLLECT STATISTICS instead of ADD STATISTICS, and
>>>>> use REMOVE STATISTICS instead of DROP STATISTICS. That way we can use
>>>>> ALTER TABLE rather than inventing a new command. 5 minute change...
>
>>> That seems like a neat idea, actually. I'm not sure COLLECT is a good choice
>>> as it suggest the statistics is actually built, but that only happens during
>>> ANALYZE. But otherwise this seems to solve the issues with keywords and it's
>>> quite simple.
>
>> But ADD is no better there.  I think ALTER TABLE .. COLLECT STATISTICS
>> isn't any worse than ALTER TABLE ... CLUSTER ON index_name.  In both
>> cases, it means, when you do this operation, do it this way.
>
>> I would suggest that instead of DROP or REMOVE, the opposite should be
>> ALTER TABLE .. NO COLLECT STATISTICS.
>
> Why is this an improvement over using already-existing keywords?

Well, if we can use existing keywords, that's better still.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company