Re: Workaround: Planner preference for tsquery filter vs. GIN index in fast text search

On Tue, Apr 22, 2014 at 10:28 AM, Heikki Linnakangas
<hlinnakangas@vmware.com> wrote:
> On 04/20/2014 07:46 AM, Oleg Bartunov wrote:
>>
>> btw, 9.4 should be wiser in case of rare+common terms, thanks to GIN
>> fast scan feature.
>
>
> Indeed, although we didn't actually do anything to the planner to make it
> understand when fast scan helps. Doing something about cost estimation is
> still on the 9.4 Open Items list, but I don't have any ideas on what to do
> about it, and I haven't heard anything from Alexander about that either.
> That means that the cost estimation issue Laurence saw is going to be even
> worse in 9.4, because GIN is going to be faster than a seq scan in more
> cases than before and the planner doesn't know about it.
>
> - Heikki

You are right, we should return to that topic.