RE: EJB versus RPG/COBOL

["David Morris" <David.Morris@xxxxxxxxxxxxx>]

Joe,

The RPG code is all RPGIV with heavy use of service programs. In Java,
updates are handled via Hibernate --> JDBC. Hibernate does use CGLIB
optimization, which means a proxy is created to access entity beans in
order to avoid the overhead of reflection. The only real difference is
that I change an object model in memory and Hibernate flushes those
changes on a commit. That means I only get net results being run, which
can be more efficient but probably insignificant in this case. I do use
set based operations for SQL input where possible to minimize object
creation and to take advantage of SMP and multithreaded database server
jobs. Primitives are used where appropriate in the Java code. Dollar
amounts are wrapped in a custom currency bean that is a thin wrapper
around a primitive double. iBatis is used when an in-memory model is
unnecessary and inefficient for things like reporting.

David Morris

>>> joepluta@xxxxxxxxxxxxxxxxx 3/12/2004 10:20:42 AM >>>
> From: David Morris
>
> On our old 730, the RPG version of these applications had that
> server pegged at 90% plus utilization. Throughput was poor due to
the
> volume of transactions. On this 825, the RPG based code only hits
about
> 30% CPU utilization. My testing shows that this Java workload will
push
> that up to about 35% CPU utilization -- more memory would increase
this
> number.

These are unique findings, David.  I'd be very interested now to see
how
the original RPG code was written and what it did.  It's my contention
that properly written RPG code will by far outperform Java code, and I
find it very difficult to comprehend a database operation where Java
matches RPG.

One way is to use set-based updates.  If you transform
record-by-record
processing to set processing, you will see performance improvements,
but
these are due to the nature of SQL, not Java.

How are you doing your updates?  Single record using JDBC?  Set at a
time SQL processing?

Joe