I think the only way for the client to be aware of server-side modifications to the database is to use a distributed cache (OSCache, Swarmcache, jcs, ...). The other way is, as Armin mentionned, not to use cache at all on the client.
For other tools to do o/r mapping see http://c2.com/cgi-bin/wiki?ObjectRelationalToolComparison Guillaume -----Message d'origine----- De : Amol Pophale [mailto:[EMAIL PROTECTED] Envoyé : mardi 4 mai 2004 12:14 À : OJB Users List Objet : Re: client-server Object Caching Hi Armin, Thanks anyway for the reply read inline comments with block letters. Regards, Amol --- Armin Waibel <[EMAIL PROTECTED]> wrote: > Hi Amol, > > I read your previous posts carefully too, but I'm > not sure that I can help. > > Amol Pophale wrote: > > Hi All, > > Please read carefully and suggest me solution. > > I am working with one MNC s/w company.My > application > > is web-based client-server application in which > client > > and server are on different machines and uses same > > database. One imp thing one client might connect > to > > more than one servers.Each server has one database > > which may be on server itself or on third machine. > > These servers stores some data in database. > > and also send a xml copy of same data on some port > > to client.web Clint get this data from server in > the > > form of xml parses this xml and creates objects > from > > that and stores in memory. If there are any > changes in > > data server notify client so client can update its > > in-memory store.[client is not using database > > directly (jdbc)because firing query on Database > every > > time is not feasible with current DB schema]But > > disadvantage of this is, if clients connect to > > multiple server [yes, there may be more than one > > servers]then performance of web-server on client > > decrease because it store data of all server in > > memory. > > Now we redesign the database schema and now client > > can connect to each server's database directly > using > > OJB PersistanceBroker API and get data. > > So you use PB-api only for read-only operations and > persist objects via > the server - right? > And on the server you don't use OJB? > Can you describe a little more? YES U ARE ABSOLUTELY CORRECT I AM MOT USING OJB ON SERVER SIDE. > > > IN Object > > cache implementation if there is some data in > cache > > and > > same data get changed by server how clients knows > this > > change and cache can be updated? > > hmm, I don't recommend to use a distributed cache on > client side this > will be overkill if you run more than a few clients. > If you allow direct > access from the client to the DB I assume > client/server/DB run in an > intranet. Do the client have to recognize changes in > DB immediately or > is latency allowed? If not I recommend not cache > data on client side or > to use the per broker cache (cache only data within > a transaction or > till the PB instance was closed), otherwise you can > use cached object > 'timeout' property of the default object cache. I CANT FIRE QUERIES EVERYTIME ON DATABSE DIRECTLY BECAUSE I WANT TO USE CACHE TO IMPROVE PERFORMANCE BUT I WANT OT KNOW HOW CLIENT CAN KNOW THAT DATABSE OBJECT IS CHANGED SO IT CAN REMOVE THAT OBJECT FROM CACHE. I HAVE ONE SOLUTION, WHEN SERVER UPDATES DATABSE IT SHOULD TELL CLIENT THAT I HAVE UPDATED DATABSE SO CLIENT CAN REMOVE THAT OBJECT FROM CACHE. HOW DO U FINFD THIS SOLUTION? ONE MORE QUESTIONS DO U KNOW OTHER TOOL BETTER THAN THIS FOR OBJECT RELATIONAL MAPPING? I HAVE READ ABOUT TOPLINK FROM ORACLE, COCOBASE, HYBERNET BUT I DONT KNOW HOW ARE THEY? AND WHAT IS DIFF BETWEEN THEM? IF U HAVE ANY INFO PLZ LET ME KNOW > > regards, > Armin > > > This is my problem > > > > Thanks & Regards > > Amol Pophale. > > > > > > > > > > > > > > > > > > > ____________________________________________________________ > > Yahoo! Messenger - Communicate instantly..."Ping" > > your friends today! Download Messenger Now > > http://uk.messenger.yahoo.com/download/index.html > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: > [EMAIL PROTECTED] > > For additional commands, e-mail: > [EMAIL PROTECTED] > > > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: > [EMAIL PROTECTED] > For additional commands, e-mail: > [EMAIL PROTECTED] > ____________________________________________________________ Yahoo! Messenger - Communicate instantly..."Ping" your friends today! Download Messenger Now http://uk.messenger.yahoo.com/download/index.html --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
