Thanks for the detailed explanation! Lukas
Werner Guttmann schrieb: > Hi, > > sure. Basically, when you start a transaction with Castor JDO using > database.begin(), internally a new TransactionContext instance will be > created. This is used to track the various user activities of this > transaction, e.g. creates, loads, ..... In Hibernate, this information > pockets associated with the TransactionContext are called '1st level cache'. > > Once a commit is issued, the information maintained within this > TransactionContext is used to prepare the various SQL statements > required to update the data in the persistence store, i.e. for example > store the new created objects in the persistence store. > > Using the mapping file, the user can configure 2nd level caches for each > mapped domain object, with varying configuration options. When used, > Castor JDO internally will use those caches when e.g. loading objects > from the persistence store. This way, once an object has been loaded > into a cache, no SQL statements will be issued anymore against the > persistence store. > > And now the last one: for detachment (JPA term) you need to associate > timestamp information with the objects being detached. In other words, > if you detach a domain object from the currently running transaction, > Castor will load it from the persistence store and attach the timestamp > of the load operation to it. At the same time, the detached object is > put into the 2nd level cache. > > Upon re-attaching the detached obejct, amongst other things, the > timestamps are being compared to see whether the object has been updated > during the detachment period. In other words, you need a cache for > detachment to work. Internally, Castor JDO uses the 2nd level cache for > this, which in my opinion is not ideal and should be refactored. > > Does this address all we talked about ? > > Werner > > Lukas Lang wrote: >> Hello Werner, >> >> I know, we discussed that last week in personal, but >> could you please again explain the different cache levels (1st, 2nd, >> update cache) of Castor to me? >> >> I'm writing to the dev list, because this might be interesting for >> others too. >> >> Thanks, >> Lukas >> >> --------------------------------------------------------------------- >> To unsubscribe from this list, please visit: >> >> http://xircles.codehaus.org/manage_email >> >> > > --------------------------------------------------------------------- > To unsubscribe from this list, please visit: > > http://xircles.codehaus.org/manage_email > > > --------------------------------------------------------------------- To unsubscribe from this list, please visit: http://xircles.codehaus.org/manage_email
