On 12 March 2014 15:52, Heikki Linnakangas <heikki.linnakangas@iki.fi> wrote:
> Allow opclasses to provide tri-valued GIN consistent functions.
>
> With the GIN "fast scan" feature, GIN can skip items without fetching all
> the keys for them, if it can prove that they don't match regardless of
> those keys. So far, it has done the proving by calling the boolean
> consistent function with all combinations of TRUE/FALSE for the unfetched
> keys, but since that's O(n^2), it becomes unfeasible with more than a few
> keys. We can avoid calling consistent with all the combinations, if we can
> tell the operator class implementation directly which keys are unknown.
>
> This commit includes a triConsistent function for the built-in array and
> tsvector opclasses.
>
> Alexander Korotkov, with some changes by me.
Patch to fix a couple typos attached.
--
Thom