Hey, I updated the guide and added a section on long transactions.
Lukas Werner Guttmann schrieb: > Thanks, Ralf. I actually didn't think of looking there. > > Anyhow, Lukas, can you please try to copy the relevant bits and pieces > to the HTML docs, and to describe the available mechanism in this area > from a user's point of view. > > This would be very nice, indeed. > > Werner > > Ralf Joachim wrote: >> Only in release notes of 1.3rc1. >> >> Werner Guttmann schrieb: >>> Great. I thought this still was progress in work. Where in the JDO >>> documentation can I (we) find information about this ? >>> >>> Werner >>> >>> Ralf Joachim wrote: >>> >>>> Hi Lukas, Werner, >>>> >>>> see my comment inline. >>>> >>>> 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. >>>>> >>>>> >>>> Since 1.3 it is possible to persist the timestamp of an object which >>>> allows to work with detached objects without any cache. In other words, >>>> if you persist timestamps detachment works without cache, if timestamp >>>> is not persisted object has to stay in 2nd level cache between detaching >>>> and reataching it. >>>> >>>>> 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 >>>>> >>>>> >>>>> >>>>> >>>> -- >>>> >>>> Syscon Ingenieurbüro für Meß- und Datentechnik GmbH >>>> Ralf Joachim >>>> Raiffeisenstraße 11 >>>> 72127 Kusterdingen >>>> Germany >>>> >>>> Tel. +49 7071 3690 52 >>>> Mobil: +49 173 9630135 >>>> Fax +49 7071 3690 98 >>>> >>>> Internet: www.syscon.eu >>>> E-Mail: ralf.joac...@syscon.eu >>>> >>>> Sitz der Gesellschaft: D-72127 Kusterdingen >>>> Registereintrag: Amtsgericht Stuttgart, HRB 382295 >>>> Geschäftsleitung: Jens Joachim, Ralf Joachim >>>> >>>> --------------------------------------------------------------------- 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 >>> >>> >>> >> -- >> >> Syscon Ingenieurbüro für Meß- und Datentechnik GmbH >> Ralf Joachim >> Raiffeisenstraße 11 >> 72127 Kusterdingen >> Germany >> >> Tel. +49 7071 3690 52 >> Mobil: +49 173 9630135 >> Fax +49 7071 3690 98 >> >> Internet: www.syscon.eu >> E-Mail: ralf.joac...@syscon.eu >> >> Sitz der Gesellschaft: D-72127 Kusterdingen >> Registereintrag: Amtsgericht Stuttgart, HRB 382295 >> Geschäftsleitung: Jens Joachim, Ralf Joachim >> >> --------------------------------------------------------------------- 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
