RE: Java and CPU

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

And this, Larry, I wholeheartedly concur with.  When someone says how slowly a 
Java application runs, I usually find that the program is trying to do 
something Java is not good at.  Examples:

Decimal arithmetic.  The BigDecimal class simply does not, nor do I think it 
ever will, perform as well as native packed decimal arithmetic in RPG.  Now, if 
the OS/400 compiler could optimize BigDecimal into packed fields with a 
particularly intelligent native optimization, that would be different, but 
until then I have a feeling that something as simple as adding a dollar and a 
half to a total amount 100 times will be much slower in Java.

Database I/O.  Even with the native driver, SQL is still inherently slower than 
native DB2 access for inserts and updates.  It may be faster on certain 
queries, but in general, business transactions that require database I/O still 
perform better with native DB2 than with SQL.  Even certain non-homogenous 
queries, such as navigating through a hierarchical table of promotions and 
deals (based on customer or order type or item number or customer and item 
number or ...) are much faster with native DB2 than with SQL.

Now, with decimal arithmetic and database I/O being two places Java 
underperforms, it's clear to me that RPG is still the language of choice for 
business logic servers, and that's why I keep repeating myself that my 
architecture of choice is Java UI connected to RPG servers.

Joe

---------- Original Message ----------------------------------
From: "Larry Loen" <lwloen@us.ibm.com>
Reply-To: JAVA400-L@midrange.com
Date: Fri, 2 Mar 2001 11:03:17 -0600

>I have generally found, in my work with customers 
that most performance problems do not relate to Java proper, 
but rather to something relating to how OS/400 is invoked or how 
the Java class library or third party application library is invoked. 
Fix that and no one seems to care much about the codegen. 

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