Re: Get more from indices.

Hello,

> > I've modified the patch to work in such a way. Also, as ISTM the patch
> > is more complicated than what the patch really does, I've simplified the
> > patch.
>
> I've revised the patch a bit. Please find attached the patch.

Thank you, but it seems to me too simplified. You made two major
functional changes.

One is, you put the added code for getrelation_info() out of the
block for the condition (info->relam == BTREE_AM_OID) (though
amcanorder would be preferable..) Anyway the reason for the place
is to guarantee 'full_ordered' index always to be orderable. I
believe the relation between them are not obvious. So your patch
has an oppotunity to make wrong assumption for possible indexes
which is not orderable but unique. Going on your way some
additional works would be needed to judge an index to be
orderable or not on checking the extensibility of pathkeys.

Another is, you changed pathkeys expantion to be all-or-nothing
decision. While this change should simplify the code slightly, it
also dismisses the oppotunity for partially-extended
pathkeys. Could you let me know the reason why you did so.

Any thoughts?

regards,

--
Kyotaro Horiguchi
NTT Open Source Software Center