Re: Rename max_parallel_degree?
Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Julien Rouhaud <julien.rouhaud@dalibo.com>,
Amit Kapila <amit.kapila16@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>,
Josh Berkus <josh@agliodbs.com>,
"David G. Johnston" <david.g.johnston@gmail.com>,
Peter Geoghegan <pg@heroku.com>, Noah Misch <noah@leadboat.com>,
David Rowley <david.rowley@2ndquadrant.com>,
Alvaro Herrera <alvherre@2ndquadrant.com>,
Magnus Hagander <magnus@hagander.net>, Bruce Momjian <bruce@momjian.us>,
PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2016-10-24T20:04:24Z
Lists: pgsql-hackers
On 10/12/16 7:58 PM, Robert Haas wrote: > I don't think it's wrong that the handling is done there, though. The > process that is registering the background worker is well-placed to > check whether there are already too many, and if it does not then the > slot is consumed at least temporarily even if it busts the cap. On > the flip side, the postmaster is the only process that is well-placed > to know when a background worker terminates. The worker process > itself can't be made responsible for it, as you suggest below, because > it may never even start up in the first place (e.g. fork() returns > EAGAIN). And the registering process can't be made responsible, > because it might die before the worker. Those are valid technical points. I have not worked out any alternatives. I'm concerned that all this makes background workers managed by extensions second-class citizens. -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services