Possibly we need something more advanced; our own reference type that can react to memory pressure by discarding pages that haven't been used in configurable amount of time.
Or perhaps we could just assume that any page that has been used once need to be used in the future and get rid of the SoftReference entirely (or otherwise janitorize it in some way). On Tue, Mar 17, 2015 at 1:24 AM, Robert Schmelzer <rob...@schmelzer.cc> wrote: > Hello, > > I recently came accross the implementation of PageSourceImpl where > PageImpl instances are softly refereneced into the pageCache: > > private final Map<CachedPageKey, SoftReference<Page>> pageCache = > CollectionFactory.newConcurrentMap(); > > This implementation caused troubles, when you bring your system into > memory preassure. The JVM will start to throw away the PageImpl to free up > memory - but during request processing he needs the PageImpl again and > starts creating it again. So basically you end up loosing your pageCache at > all and start creating the PageImpl instances on every request, which take > way to much time and takes load onto the CPU. So basically you are hiding a > memory problem by making the system slow and raise CPU load. > > I would suggest to use "normal" references for the PageCache or at least > only do SoftReferences only when not in production mode. Otherwise we are > going to cover memory problems for too long. > > What do you think about that? > > Robert > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tapestry.apache.org > For additional commands, e-mail: users-h...@tapestry.apache.org > > -- Howard M. Lewis Ship Creator of Apache Tapestry The source for Tapestry training, mentoring and support. Contact me to learn how I can get you up and productive in Tapestry fast! (971) 678-5210 http://howardlewisship.com @hlship
