> From: Gerhard Froehlich [mailto:[EMAIL PROTECTED]] > > Hi, > > >-----Original Message----- > >From: Britton, Colin [mailto:[EMAIL PROTECTED]] > >Sent: Monday, January 28, 2002 5:59 PM > >To: [EMAIL PROTECTED] > >Subject: RE: cvs commit: MRUMemoryStore.java FilesystemQueueObject.java > > > > > >For our application I want to not only cache from memory, but also store > >the objects on the fileSystem (as the cost of generation in our app can > >be high). With the change so that items are only written to the file > >system when the number of memory objects reaches max and this.free() is > >called it seems that we loose this capability unless we set the memory > >objects to a small number (which defeats the objective of the cache and > >having lots of memory). One of the benefits of the old way was that if > >the VM unexpectedly quits we had the file system cache for all the items > >that were in memory. Also all memory objects are lost after shutdown, > >maybe it would also be also a good idea to write the memory objects to > >disk on a formal shutdown (this was not needed with the old method) if > >the queue method is not returned. > > You can't imagine how much thoughts I wasted for that issue. I will > explain you them (again): > > a) The old way stored every object twice. First in Memory, Second on the > Filesystem. That was a very _expensive_ operation. We needed an extra > thread which did all that serialization and he eated performance. > The only real advantage was to have the objects persistent after a JVM > restart. Therefor I never had a good feeling about that. This are too > little advantages. > > And besides, how often crashes the JVM. Every day, weekly, monthly. How long > does it take till the old caching status is reached? The first user gets > a slow page. The next a quick one. > > I wanna have a clean implementation. This other issues are parts of the > adaptive > caching or something else I say. It must be simple! > > b) The new way behaves more like a normal OS cache. First everything is > handeld > in memory. If this is running, old ones are swapped out to make room for > others.
New store implementation - does it swaps to file system when removing items from the stores? > At least I see no way how to handle a formal shutdown. Did would be the > best. Then we could catch this event and save the memory store down to > the Filesystem. No problems with this. Implement Disposable interface. Vadim > Maybe the others do have a idea here. > > Gerhard > > +----------------------------------------------+ > My parents have been visiting me for a few days. > I just dropped them off at the airport. > They leave tomorrow. > +----------------------------------------------+ --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, email: [EMAIL PROTECTED]
