On Mon, 2007-08-27 at 09:43 -0700, Dustin Sallings wrote: > On Aug 27, 2007, at 4:39 , Wojtek Meler wrote: > > > I think memcached server should be able to broadcast some kind of > > update > > log that other instances would listen. It would also enable event > > notification on state changes. > > Anyone interrested in such feature ? > > I'm somewhat interested in being able to connect to an instance and > have it start feeding me notifications for anything that would > invalidate the cache for a particular key. > > I haven't got around to doing anything about it, though.
I have thought about doing this, too -- the issues I'm raising are the ones that were raised to me when I started talking about the idea... A major design goal of memcache is to have all operations be roughly order 1. A notification system would be order n with the number of listeners on that key. Also, where would the memory for keeping track of listeners go? I had originally thought that this would make the most sense with per-key notifications. Maybe it would be better to do this as a global notification system? That might entail adding one new keyword to the protocol which puts a TCP session into notification mode until the end of the session. Aaron
