Re: Ticket 118: Exclusion constraints

Le 12/07/2010 12:13, Magnus Hagander a écrit :
> On Sat, Jul 10, 2010 at 22:49, Guillaume Lelarge <guillaume@lelarge.info> wrote:
>> Hi,
>>
>> At least, I finally did it :)
>>
>> This patch adds support for exclusion constraint (9.0 new feature). All
>> examples from Magnus's talk (Beyond Unique) work with this patch.
>>
>> Anyway, this patch needs more work:
>>
>> 1. Displayed in both Constraints and Indexes
>>
>> I don't know why but each exclusion constraint is displayed two times.
>> In the indexes node (where it doesn't belong), and in the constraints
>> node (where it belongs). Any idea why? should not be too hard to find
>> out, but I'm unable to find it right now.
>
> How do we do it with Primary Keys? It's the same thing - both an index
> and a constraint. There should be some code to hide it, thus similar
> code should be needed here.
>

Actually, I tried to understand how it worked for primary keys and
unique indexes. So far, I'm still wondering how it could hide them.

>> 2. Need an icon
>>
>> I copied the unique constraint icon, but we really need another one for
>> this specific constraint.
>>
>> 3. Probably some misunderstanding of the feature
>>
>> Should we propose all operators for the columns? or just the ones
>> related to 1. the operator class 2. the column's type 3. something else?
>> actually, I propose all of them. But I don't think this is what we
>> should do.
>
> You need to show only commutative operators.
>
> That may be we need to filter on oid=oprcom in pg_operator - I'm not
> sure of that though, I didn't really investigate, but it looks like a
> reasonable thing.
>
> And yes, it should definitely be filtered on the column types.
>
>
>> In Magnus's talk, I see that only GiST is supported right now as an
>> index method. In PostgreSQL fine manual, it says that, to be usable, an
>> index should provide the amgettuple method. And I see three of them
>> support this method. Who's wrong? :)
>
> Trust The Fine Manual.
>
> Always remember that some of those things may also have changed since
> my talk :-)
>

Sure.

Thanks for your comments, I'll work on this at a later time.


--
Guillaume
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