Re: [v9.5] Custom Plan API

* Kouhei Kaigai (kaigai(at)ak(dot)jp(dot)nec(dot)com) wrote:
> GPU has workloads likes and dislikes. It is a reasonable idea to list up
> operators (or something else) that have advantage to run on custom-path.
> For example, numeric calculation on fixed-length variables has greate
> advantage on GPU, but locale aware text matching is not a workload suitable
> to GPUs.

Right- but this points out exactly what I was trying to bring up.

Locale-aware text matching requires running libc-provided code, which
isn't going to happen on the GPU (unless we re-implement it...).
Aren't we going to have the same problem with the 'numeric' type? Our
existing functions won't be usable on the GPU and we'd have to
re-implement them and then make darn sure that they produce the same
results...

We'll also have to worry about any cases where we have a libc function
and a CUDA function and convince ourselves that there's no difference
between the two.. Not sure exactly how we'd built this kind of
knowledge into the system through a catalog (I tend to doubt that'd
work, in fact) and trying to make it work from an extension in a way
that it would work with *other* extensions strikes me as highly
unlikely. Perhaps the extension could provide the core types and the
other extensions could provide their own bits to hook into the right
places, but that sure seems fragile.

Thanks,

Stephen