Re: CustomScan in a larger structure (RE: CustomScan support on readfuncs.c)

On Mon, Jan 25, 2016 at 8:06 PM, Kouhei Kaigai <kaigai(at)ak(dot)jp(dot)nec(dot)com> wrote:
> Sorry for my late response. I've been unavailable to have enough
> time to touch code for the last 1.5 month.
>
> The attached patch is a revised one to handle private data of
> foregn/custom scan node more gracefully.
>
> The overall consensus upthread were:
> - A new ExtensibleNodeMethods structure defines a unique name
> and a set of callbacks to handle node copy, serialization,
> deserialization and equality checks.
> - (Foreign|Custom)(Path|Scan|ScanState) are first host of the
> ExtensibleNodeMethods, to allow extension to define larger
> structure to store its private fields.
> - ExtensibleNodeMethods does not support variable length
> structure (like a structure with an array on the tail, use
> separately allocated array).
> - ExtensibleNodeMethods shall be registered on _PG_init() of
> extensions.
>
> The 'pgsql-v9.6-custom-private.v3.patch' is the main part of
> this feature. As I pointed out before, it uses dynhash instead
> of the self invented hash table.

On a first read-through, I see nothing in this patch to which I would
want to object except for the fact that the comments and documentation
need some work from a native speaker of English. It looks like what
we discussed, and I think it's an improvement over what we have now.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company