Re: [HACKERS] WIP: [[Parallel] Shared] Hash

On Tue, Jan 10, 2017 at 8:56 PM, Peter Geoghegan <pg@heroku.com> wrote:
> Instead of all this, I suggest copying some of my changes to fd.c, so
> that resource ownership within fd.c differentiates between a vfd that
> is owned by the backend in the conventional sense, including having a
> need to delete at eoxact, as well as a lesser form of ownership where
> deletion should not happen.

If multiple processes are using the same file via the BufFile
interface, I think that it is absolutely necessary that there should
be a provision to track the "attach count" of the BufFile.  Each
process that reaches EOXact decrements the attach count and when it
reaches 0, the process that reduced it to 0 removes the BufFile.  I
think anything that's based on the notion that leaders will remove
files and workers won't is going to be fragile and limiting, and I am
going to push hard against any such proposal.

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