Publish autovacuum informations

Hey,

There are times where I would need more informations on the autovacuum
processes.

I'd love to know what each worker is currently doing. I can get something
like this from the pg_stat_activity view but it doesn't give me as much
informations as the WorkerInfoData struct.

I'd also love to have more informations on the contents of the tables list
(how many tables still to process, which table next, what kind of
processing they'll get, etc... kinda what you have in the autovac_table
struct).

All in all, I want to get informations that are typically stored in shared
memory, handled by the autovacuum launcher and autovacuum workers. I first
thought I could get that by writing some C functions embedded in an
extension. But it doesn't seem to me I can access this part of the shared
memory from a C function. If I'm wrong, I'd love to get a pointer on how to
do this.

Otherwise, I wonder what would be more welcome: making the shared memory
structs handles available outside of the autovacuum processes (and then
build an extension to decode the informations I need), or adding functions
in core to get access to this information (in that case, no need for an
extension)?

Thanks.

Regards.

--
Guillaume.
http://blog.guillaume.lelarge.info
http://www.dalibo.com