On Wed, Apr 22, 2020 at 2:36 PM Andres Freund <andres@anarazel.de> wrote:
> > If it's any consolation, I had the same idea very recently while
> > chatting with Amit Langote. Maybe it's a bad idea, but you're not the
> > only one who had it. :-)
>
> That seems extremely hard, given our current infrastructure. I think
> there's actually a good case to be made for the idea in the abstract,
> but ... The amount of logic the ExecInit* routines have is substantial,
> the state they set up ss complicates. A lot of nodes have state that is
> private to their .c files. All executor nodes reference the
> corresponding Plan nodes, so you also need to mock up those.
Right -- the idea I was talking about was to create a Plan tree
without using the main planner. So it wouldn't bother costing an index
scan on each index, and a sequential scan, on the target table - it
would just make an index scan plan, or maybe an index path that it
would then convert to an index plan. Or something like that.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
