Re: proposal: persistent plpgsql plugin info - field plugin_info for plpgsql_function structure

2013/12/31 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>

> Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> writes:
> > Requested feature doesn't help me implement this concept 100%, but helps
> > with check If I worked with some instance of function or not. And inside
> > core a implementation is cheap. Outside core it is a magic with hash and
> > checking transaction id (about 200 lines). When I worked on extension for
> > coverage calculation I had to solve same task, so I think so this
> variable
> > can be useful generally for similar tasks.
>
> Are you proposing a reserved-for-plugins "void*" in struct
> PLpgSQL_function similar to the existing one in struct PLpgSQL_execstate?
>
> If so, while it sounds harmless in itself, I think your argument above is
> actually the strongest reason *not* to do it. The existing plpgsql plugin
> infrastructure is incapable of supporting more than one plugin at a time,
> and the more attractive we make it, the more likely we're going to have
> conflicts. It was never meant to support anything but the plpgsql
> debugger. Before we start aiding and abetting the development of other
> plugins, we need a design that allows more than one of them to be
> installed.
>

ok, what we can do better?

Can be solution a callback on plpgsql_HashTableInsert and
plpgsql_HashTableInsert? With these callbacks a relation between function
and some plugin data can be implemented more simply.

Regards

Pavel

>
> regards, tom lane
>