On Thu, Nov 8, 2012 at 6:23 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Simon Riggs <si...@2ndquadrant.com> writes: >> On 8 November 2012 20:36, Jeff Janes <jeff.ja...@gmail.com> wrote: >>> It does not seem outrageous to me that there would be real-world >>> conditions in which invalidations would be sent more than once a >>> minute over prolonged periods, so this total starvation seems like a >>> bug. > >> Yes, its a bug, but do you really believe the above? In what cases? > > It doesn't take a whole lot of DDL to provoke an sinval overrun, if > the recipient process is just sitting idle and not servicing the > messages. I think Jeff's concern is entirely valid.
So, do we need a sinval overrun or just a sinval message to provoke starvation? The former would be bad but the latter would be really, really bad. IIRC the queue has 4K entries, and IIRC a single DDL operation might provoke a couple of sinvals, but I'm thinking that somebody would probably have to be creating >1024 temp tables a minute to overrun the queue, which is very possible but not necessarily common. OTOH, creating 1 temp table a minute would hit a much broader swath of users. -- 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
