On 9 November 2012 13:42, Robert Haas <[email protected]> wrote: > On Thu, Nov 8, 2012 at 6:23 PM, Tom Lane <[email protected]> wrote: >> Simon Riggs <[email protected]> writes: >>> On 8 November 2012 20:36, Jeff Janes <[email protected]> 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.
The point is moot because latches don't work that way anymore. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
