+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
