Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Aug 28, 2017 at 6:35 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Maybe parallel_aware should have more than two values, depending
>> on whether the result of the node is context-dependent or not.
> It seems likely the whole concept of parallel_aware is only only a
> zero-order approximation to what we really want.
Yeah, I agree --- but it's also clear that we don't yet know what it
should be. We'll have to work that out as we accrete more functionality.
In the meantime, I think what we should do is commit the bug fix more or
less as I have it, and then work on Amit's concern about losing parallel
efficiency by separating the resetting of shared parallel-scan state
into a new plan tree traversal that's done before launching new worker
processes. The only real alternative is to lobotomize the existing rescan
optimizations, and that seems like a really poor choice from here.
regards, tom lane