Horton

Re: Snapshot synchronization, again...

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jim Nasby <jim@nasby.net>
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: 2011-03-02T04:54:11Z
Lists: pgsql-hackers 
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.

			regards, tom lane