Re: WIP: Covering + unique indexes.

On Tue, Dec 1, 2015 at 7:53 AM, Anastasia Lubennikova
<a.lubennikova@postgrespro.ru> wrote:
> If we don't need c4 as an index scankey, we don't need any btree opclass on
> it.
> But we still want to have it in covering index for queries like
>
> SELECT c4 FROM tbl WHERE c1=1000; // uses the IndexOnlyScan
> SELECT * FROM tbl WHERE c1=1000; // uses the IndexOnlyScan
>
> The patch "optional_opclass" completely ignores opclasses of included
> attributes.

OK, I don't get it.  Why have an opclass here at all, even optionally?

-- 
Robert Haas
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