Re: Custom Scan APIs (Re: Custom Plan node)

* Robert Haas (robertmhaas(at)gmail(dot)com) wrote:
> For what it's worth, and I can't claim to have all the answers here,
> this doesn't match my expectation. I think we'll do two kinds of
> parallelism. One will be parallelism within nodes, like parallel sort
> or parallel seqscan. Any node we parallelize this way is likely to be
> heavily rewritten, or else to get a sister that looks quite different
> from the original.

Sure.

> The other kind of parallelism will involve pushing
> a whole subtree of the plan into a different node. In this case we'll
> need to pass data between nodes in some different way (this was one of
> the major reasons I designed the shm_mq stuff) but the nodes
> themselves should change little if at all.

It's that "some different way" of passing data between the nodes that
makes me worry, but I hope you're right and we won't actually need to
change the interfaces or the nodes very much.

Thanks,

Stephen