Re: Multi-column distinctness.

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Tue, Oct 20, 2015 at 10:51 AM, Tomas Vondra
> <tomas(dot)vondra(at)2ndquadrant(dot)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?

regards, tom lane