[hibernate-dev] Re: [jbosscache-dev] REPEATABLE_READ in JBC as Hibernate 2nd Level Cache

[Manik Surtani]

AFAIR the last time we discussed this (last summer in Austin with  
Steve and Gavin) we came to the conclusion that R_C was optimal for  
the 2LC use case.

On 17 Jul 2008, at 22:59, Brian Stansberry wrote:

Hmm, good point. Potentially also Session.refresh(...), although I'm  
not sure if the implementation of that method skips the 2LC and goes  
right to the db.

Paul Ferraro wrote:

After thinking this through, the only scenario I can think of where  
the
2LC would be subject to a repeated read is after a session cache
eviction (i.e. via Session.clear() or Session.evict(...)).  Without
REPEATABLE_READ isolation on the 2LC, any subsequent request  
withing the
same transaction for an evicted entity could return an updated  
value, if
the cache was updated by a concurrent request.


You'd need to check with Steve on this, but to the best of my  
knowledge, once a session has started, it copies stuff to a "first- 
level cache" which is a Map associated with the session.  A  
Session.clear()/evict() would only flush the 2LC, the 1LC would still  
be intact to provide R_R to the caller.  Although it does sound a bit  
odd that a clear() or evict() won't affect 1LC and go straight to 2LC,  
so I could be wrong.  :-)

Cheers,
Manik

--
Manik Surtani
Lead, JBoss Cache
[EMAIL PROTECTED]






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