[News.eclipse.technology.eclipselink] Re: Switching Maya to JPA / Eclips

[shaun.smith@xxxxxxxxxx (Shaun Smith)]

Hi Tim,

Timothy Webb wrote:

> ...
> One is that when running against certain
> databases, we've noticed connection timeout issues that cause various
> unexpected failures.

In my use of TopLink Essentials in RCP I was using the internal connection 
pooling without any problems but I didn't have long periods of idle time 
so I never experienced any timeout problems.  Are you using the built in 
connection pooling or are you using you're container's connection pool?

> Two is that there appears to be some caching of
> objects occurring.

There is definitely caching going on by default ;-).  Take a look at this 
blog [1] on the TopLink Essentials caching architecture.  There are many 
ways to tune the cache.  If you want objects to be reread from the 
database fresh in each transaction then you want to set the 
toplink.cache.shared.<ENTITY> property to false.  You can do this globally 
for all classes with the toplink.cache.shared.default property.

> Our runtime is currently a standalone OSGi container using the Jetty
> server that has been integrated as part of the Equinox project.  When
> running in this environment, is there any recommendation you would 
> have regarding connection configuration and caching when in 
> development vs. full deployment?

Typically, cache configuration is the same in dev and deployment since it 
has a huge impact on the program.  Changes to the cache config can lead to 
significantly different results so best to get it setup as per your needs 
and leave it alone.

--Shaun

[1] 
http://weblogs.java.net/blog/guruwons/archive/2006/09/understanding_t.html