Taking this one step further, you want to have your single instance of the cache on a highly available machine, like your database server. Since you need logic in it for data consistency, rather than "reinvent the wheel", the easiest way to improve performance is to tune the actual database itself for more caching. (ie large buffer pools, etc.)
-----Original Message----- From: Juan Pablo Lorandi [mailto:rifle@;CODEFOUNDRY.COM] Sent: Monday, October 28, 2002 3:58 PM To: [EMAIL PROTECTED] Subject: Re: Singleton accessing EntityBean working as cache It's a bad idea. The closest you might get is to build a cache with a Stateful Session Bean. But for read/write data to be consistent at all times, you'll need to have a single cache for the entire cluster, because: 1) Otherwise two instances of the caches might execute concurrently. 2) Synchornization of the caches may prove to be even more expensive than no cache at all. Basically, to implement a cache with write capabilities efficiently(and regards for data consistency), you must have guarantees that there's only one party executing the writes, and that you control it. You can't achieve this in a cluster in an efficient way. It could be possible, however, to implement more efficient caches if requirements on transaction isolation aren't high, but that implies the possibility of data corruption. My 2c, Juan Pablo Lorandi Chief Software Architect Code Foundry Ltd. [EMAIL PROTECTED] Barberstown, Straffan, Co. Kildare, Ireland. Tel: +353-1-6012050 Fax: +353-1-6012051 Mobile: +353-86-2157900 www.codefoundry.com > -----Original Message----- > From: A mailing list for Enterprise JavaBeans development > [mailto:EJB-INTEREST@;JAVA.SUN.COM] On Behalf Of Mike Landy > Sent: Monday, October 28, 2002 7:25 PM > To: [EMAIL PROTECTED] > Subject: Singleton accessing EntityBean working as cache > > > Hello! > > I have a situation where a Singleton class should offer an > interface to a read/write cache object. Singleton class will > run in clustered environment so, I thing there would be as > many Singletons as there are JVMs. > > Is it ok/possible to use EntityBean or EntityBean and it's > collection class member as an read/write cache object? > > I have thougt about following functionality: > > 1. EntityBean reads data from Database to e.g. a collection > class (which works as a cache). > > 2. A Singleton class is created and is working as an > interface to WebApplication (client). > > 3. WebApplications can read and update data that is hold in > EntityBean's collection class. Singleton class provides > interface for read and write actions. > > 4. Web Container is clustered, so there will be as many > singleton classes as JVMs. > > So, the need is to have consistent data in EntityBean's > collection class. > > I'm not sure if this approach is good at all..., so I would > like to get tips how build a better/working solution. > > If someone has build same kind of solution (or better one), I > would be happy to get hints/tips. > > Thanks, > > Mike > > ============================================================== > ============= > To unsubscribe, send email to [EMAIL PROTECTED] and > include in the body of the message "signoff EJB-INTEREST". > For general help, send email to [EMAIL PROTECTED] and > include in the body of the message "help". > > =========================================================================== To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff EJB-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help". DISCLAIMER: The information contained in this e-mail may be confidential and is intended solely for the use of the named addressee. Access, copying or re-use of the e-mail or any information contained therein by any other person is not authorized. If you are not the intended recipient please notify us immediately by returning the e-mail to the originator. ==========================================================================To unsubscribe, send email to [EMAIL PROTECTED] and include in the body of the message "signoff EJB-INTEREST". For general help, send email to [EMAIL PROTECTED] and include in the body of the message "help".
