Re: index-only count(*) for indexes supporting bitmap scans

>>>>> "Alexander" == Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru> writes:

 Alexander> Structurally, the patch consists of two major parts: a
 Alexander> specialized executor node

Why?

It strikes me that the significant fact here is not that we're doing
count(*), but that we don't need any columns from the bitmap heap scan
result.  Rather than creating a whole new node, can't the existing
bitmap heapscan be taught to skip fetching the actual table page in
cases where it's all-visible, not lossy, and no columns are needed?

(this would also have the advantage of getting parallelism for free)

-- 
Andrew (irc:RhodiumToad)