Re: [ANNOUNCE] IMCS: In Memory Columnar Store for PostgreSQL

On Sun, Jan 5, 2014 at 1:44 PM, james <james@mansionfamily.plus.com> wrote:
> I'm intrigued - how are the handles shared between children that are peers
> in the current scheme?  Some handle transfer must already be in place.

That's up to the application.  After calling dsm_create(), you call
dsm_segment_handle() to get the 32-bit integer handle for that
segment.  Then you have to get that to the other process(es) somehow.
If you're trying to share a handle with a background worker, you can
stuff it in bgw_main_arg.  Otherwise, you'll probably need to store it
in the main shared memory segment, or a file, or whatever.

> Could you share the handles to an immortal worker if you want to reduce any
> potential impact on the postmaster?

You could, but this seems like this justification for spawning another
process, and how immortal is that worker really?

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