Re: Snapshot synchronization, again...

Jim Nasby <jim@nasby.net>

From: Jim Nasby <jim@nasby.net>

To: Tom Lane <tgl@sss.pgh.pa.us>

Cc: Robert Haas <robertmhaas@gmail.com>, Joachim Wieland <joe@mcknight.de>, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>, Alvaro Herrera <alvherre@commandprompt.com>, Noah Misch <noah@leadboat.com>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2011-03-03T23:52:58Z

Lists: pgsql-hackers

On Mar 1, 2011, at 10:54 PM, Tom Lane wrote:
> Jim Nasby <jim@nasby.net> writes:
>> Dumb question: Is this something that could be solved by having the postmaster track this information in it's local memory and make it available via a variable-sized IPC mechanism, such as a port or socket? That would eliminate the need to clean things up after a crash; I'm not sure if there would be other benefits.
> 
> Involving the postmaster in this is entirely *not* reasonable.  The
> postmaster cannot do anything IPC-wise that the stats collector couldn't
> do, and every additional function we load onto the postmaster is another
> potential source of unrecoverable database-wide failures.  The PM is
> reliable only because it doesn't do much.

Makes sense. Doesn't have to be the postmaster; it could be some other process.

Anyway, I just wanted to throw the idea out as food for thought. I don't know if it'd be better or worse than temp files...
--
Jim C. Nasby, Database Architect                   jim@nasby.net
512.569.9461 (cell)                         http://jim.nasby.net