Re: Multi-column distinctness.

On Tue, Oct 20, 2015 at 10:51 AM, Tomas Vondra
<tomas.vondra@2ndquadrant.com> wrote:
>> Koyotaro's changes to force COLUMN to be required won't get through.
>>
>> 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.

-- 
Robert Haas
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