Non-sticky would be rather bad for Wicket performance/programming model. The default of wicket is to redirect after an event to a get request which renders a buffered response. The buffered response is only available on the jvm that handled the original request. If the buffered response is not available, it would require rendering all content again, requiring fetching all entities, etc. from the database.
Martijn On Mon, Mar 9, 2009 at 3:03 PM, Martin Grotzke <martin.grot...@javakaffee.de> wrote: > On Mon, 2009-03-09 at 13:07 +0100, Martijn Dashorst wrote: >> Starts to sound like a form of premature optimization. If you are new >> to Wicket, why do you want to implement a memcached session store? >> What is the usecase? > We're starting a new project (the relaunch of a big ecommerce system) > and want to be able to scale out (just throw in new hardware when > traffic grows). Additionally we have the requirement of session > failover, both in standard operations and for deployments. > > We're discussing non-sticky vs. sticky sessions here and for non-sticky > sessions memcached (as caching layer in addition to sessions stored in a > database) is a good candidate, as you don't replicate the changed > session to all other nodes, but only to the primary node for this > session id. This is an important aspect for beeing able to scale out. > > Concerning non-sticky/sticky/memcached/whatever we're not decided yet, > still running in evaluation mode :) > > Cheers, > Martin > > >> >> Martijn >> >> On Mon, Mar 9, 2009 at 9:56 AM, Martin Grotzke >> <martin.grot...@javakaffee.de> wrote: >> > On Sun, 2009-03-08 at 16:56 -0700, Victor Igumnov wrote: >> >> I wrote a memcached session manager store for jetty, that our wicket >> >> app utilizes. Works well, except I can't open source it, >> >> since it was created on the company's dime ;-( >> > Well, most interesting things are not so simple to realize that one can >> > do it in its spare time. But the good point is that we can do such >> > interesting things in our job :) >> > >> >> >> >> Here is my opinion on memcached as a session store. >> >> >> >> Memcached will not work well as a wicket session store, due to 1mb >> >> size limits. >> > Good to know, I wasn't aware of this restriction (I still need to read >> > more about this for details). So one is forced to handle resources >> > eating much memory (e.g. fileupload) not via session, which is the case >> > even without this 1 mb size limit :) >> > >> > Do you have a case where this limit is important especially for wicket? >> > >> >> You honestly don't want to serialize anything past 100kb >> >> in size due to performance reasons. >> > Right. >> > >> >> That said, It works best if you >> >> use memcached as a container httpsessionstore with the wicket >> >> secondlevelcache diskpagestore. The only thing you need to serialize >> >> is the last pagemap which should only be 50kb in size max. You still >> >> get fail over since the last page map is distributed. >> > And I have to read about page maps (I'm really new to wicket as you >> > see :)). AFAIK page maps store a configurable numer of versioned pages >> > for back-button support and versioned pages. >> > >> >> >> >> One thing you need to be careful with is not referencing anything that >> >> got stored on disk from your active pagemap, it will spiral into a >> >> stack overflow. >> >> >> >> https://issues.apache.org/jira/browse/WICKET-2138 >> > Thanx! We would need to setup tests to be sure that this won't happen. >> > >> > Thanx for your input, >> > cheers, >> > Martin >> > >> > >> >> >> >> >> >> -Victor >> >> >> >> On Mar 8, 2009, at 3:25 PM, Martijn Dashorst wrote: >> >> >> >> > You can check the TIM integration work from the Terracotta guys. That >> >> > should make things easier, and you could even try it out, perhaps >> >> > saving a memcached implementation completely :) >> >> > >> >> > Martijn >> >> > >> >> > On Sun, Mar 8, 2009 at 11:01 PM, Martin Grotzke >> >> > <martin.grot...@javakaffee.de> wrote: >> >> >> Hi, >> >> >> >> >> >> we're just thinking about a session store using memcached. I just >> >> >> want >> >> >> to ask if somebody already implemented this (and wants to share) >> >> >> before >> >> >> we implement this. >> >> >> >> >> >> Btw, is there some documentation about ISessionStore semantics, in >> >> >> addition to javadocs? I would be interested in the order in which the >> >> >> different methods would be invoked. >> >> >> >> >> >> Thanx && cheers, >> >> >> Martin >> >> >> >> >> >> >> >> > >> >> > >> >> > >> >> > -- >> >> > Become a Wicket expert, learn from the best: http://wicketinaction.com >> >> > Apache Wicket 1.3.5 is released >> >> > Get it now: http://www.apache.org/dyn/closer.cgi/wicket/1.3. >> >> > >> >> > --------------------------------------------------------------------- >> >> > To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org >> >> > For additional commands, e-mail: users-h...@wicket.apache.org >> >> > >> >> >> >> >> >> --------------------------------------------------------------------- >> >> To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org >> >> For additional commands, e-mail: users-h...@wicket.apache.org >> >> >> > >> >> >> > -- Become a Wicket expert, learn from the best: http://wicketinaction.com Apache Wicket 1.3.5 is released Get it now: http://www.apache.org/dyn/closer.cgi/wicket/1.3. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@wicket.apache.org For additional commands, e-mail: users-h...@wicket.apache.org
