On Sun, May 22, 2011 at 9:54 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> If not, then how about jiggering things somehow so that only one >> server process needs to run the hack? Perhaps it can drop the result >> in a file or shared memory or something from which the remaining >> backends can read it out without having to redo all that work? >> Admittedly there is a synchronization problem there I'm not quite sure >> how to solve. > > Well, the main point in my mind is that the process is so damn expensive > that we don't want to run it at all, ever, if we can avoid it. > > We could imagine launching a postmaster child to compute the result, > as you suggest. And it would work 99.9% of the time, because probably > nobody would remove the setting from postgresql.conf within a few > seconds of having started the postmaster. But also, 99.999% of the time > it would be completely wasted effort because the DBA wouldn't remove the > postgresql.conf setting at all, ever.
Well, by that argument, we ought not to worry about masterminding what happens if the DBA does do such a thing -- just run the whole process and damn the torpedoes. If it causes a brief database stall, at least they'll get the correct behavior. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
