Re: Indexam interface proposal

Martijn van Oosterhout wrote:
> On Mon, Mar 19, 2007 at 12:23:01PM +0000, Heikki Linnakangas wrote:
>> Currently amgettuple returns one matching tuple at a time, in index
>> order. I'm proposing two changes to add support for
>> - candidate matches
>
> IIRC indexes can already ask to have the system recheck conditions on
> returned tuples. For example GiST can return more tuples than actually
> match. That's what the amopreqcheck column is for in pg_amop.

Right, except that flag is per operator in operator class, and what I'm
proposing is that the index could pass a flag per tuple in the scan.
Some tuples in the scan might need rechecking, some might not. The need
for rechecking in clustered indexes is orthogonal to the need arising
from the lossyness of GiST operators.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com