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From John Sisson <jrsis...@gmail.com>
Subject Re: OpenEJB JIRAs for 1.1.1 - bugs or features ?
Date Mon, 17 Jul 2006 23:28:39 GMT
+1 to all of these if you have the time to get them into 1.1.1.  Even 
though some can be considered features they are really resolving 
usability issues.  After all, there is no point having a server that is 
compliant but not usable in the real world.

Thanks,
John

Matt Hogstrom wrote:
> I opened 3 JIRAs that affect CMP deployment, Session bean performance 
> and consistency.
>
> The JIRA's in question are:
>
> GERONIMO-2127 - Expose ability to use SELECT FOR UPDATE
> GERONIMO-2129 - Allow user to specify pool size on Stateless Session 
> Beans
> GERONIMO-2128 - Allow user to specify an Isolation Level on a CMP Bean
>
> I think  these items can be argued in two ways.  Bugs and features.
>
> Based on my experience with CMP beans what we have for Geronimo is 
> fully compliant with the J2EE specification.  We pass the tests and 
> are compliant.
>
> However, our current implementation does not allow for a user to 
> deploy an application that will ensure data consistency.  For 
> instance, if one is using Oracle as the database, which operates at 
> Read Committed by default, two competing applications will possible 
> overlay data from one another with no notification at all.  In order 
> to properly provide for ACID properties a SELECT FOR UPDATE needs to 
> be provided so one application can block another.  I consider this a 
> bug since even though the implementation "is compliant" it is also 
> unusable unless your data is read-only or you can guarantee no 
> conflicts in some other way.
>
> The second issue goes to consumability as well as accuracy.  Stateless 
> session beans are traditionally used as facades and wrappers for Tx.  
> They are also used to store information that is transient but expected 
> to be longer lived than a single use.  The SLSB in OpenEJB has a pool 
> size of one and will make some applications perform poorly and perhaps 
> malfunction.
>
> In the case of SPECjAppServer it will do both.  The SLSB is used in 
> that application as a temporary cache for keys used to insert into a 
> database.  The current behaviour is that on every request a new block 
> of keys is retrieved from the Key database.  For SPECj and DayTrader 
> it results in deadlocks and collided keys.  The Pool (which does exist 
> but is fixed at a size of 1) will eliminate this problem.
>
> 2128 is similar to 2127 in so far as using database isolation to 
> provide ACID properties it allows for multiple Isolation levels to be 
> used such that RDBMs such as DB2 or Derby can perform better. Although 
> this isn't required for ACID properties it does require a schema 
> change to OEJB 2.1.1.
>
> All of these JIRA's can be implemented without disrupting current 
> applications so I believe we should include them in 1.1.1.
>
> The changes are actually limited to OEJB and TranQL which are 
> components of G.
>
> My vote is to include these JIRA's.
>
> Matt
>


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