Database Reference
In-Depth Information
tion's logic, and apparently, old JPA is not enough. The latest JPA 2.
x
(JSR 338) covers
most of aspects of access schema-less DB, in addition to the traditional implementations.
Polyglot Persistence allows the abstracting of JPA's implementations even further, and
with in-memory data-grid Coherence (JSR 107), we can achieve the highest level of data
abstraction and availability.
When discussing a DB's role in an SOA technical infrastructure, it is quite interesting to
mention the number of critical errors solely related to DB faults/mishandling. Does the
following list look familiar?
• We dequeued the inbound message from the JMS queue, but failed to persist it in
the DB because of tablespace problems. Where can we find the message for pro-
cess recovery? (By the way, should we mention that the queue retention time was
set to
0
?)
• During the night batch job, one longops runs out of rollback size as it was not big
enough. About 25 percent of our active orders failed CRM-ERP synchronization
and now applications are out of sync. Worse, policy-based automated recovery
triggered automatically, but it also failed for the same reason. Now a manual
clean-up is necessary. (The DBA forgot to assign a longops transaction to the one
big rollback segment.)
• BPEL tried to dehydrate the process, but the tablespace was full. (Obviously, the
SCA audit level was not tuned, but it seems that the DBA didn't monitor ta-
blespace usage as well.)
From our experience, we can say that about 60 percent of all SCA crashes in production
are caused by DB-related reasons.
The implementation of the State Deferral pattern for orchestrated services in terms of data
persistence has significant impact on storage management, where one of the critical opera-
tions is the process of data cleansing. Oracle provides purge scripts together with purge
strategies, depending on your operational requirements.
The Oracle application server
The core strategic assets of the Oracle WebLogic application server are interactively de-
WebLogic Application Server together with the DB is another keystone in SOA founda-
tion. It's an engine of engines, so to say. All that you will build, deploy, execute, or con-
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