RE: [SYSTEM21] Another V5R2 question

["Brunk, Kevin" <KBrunk@xxxxxxxxxxxx>]

My understanding is that what IBM has done isn't that they made SQL less 
efficient.  Rather, they have made their version of SQL more compliant with the 
ANSI standard. Prior releases/versions allowed programmers to be a little 
"sloppy" in how they coded SQL and somehow the optimizer or the compiler or ? 
made up for the poor coding.  

I also believe they've supposedly improved the efficiency of the optimizer so 
that well-coded statements should perform better.

There is a redbook on this topic:  "Preparing for and Tuning the V5R2 SQL Query 
Engine on DB2 Universal Database for 
iSeries".  This Redbook gives a broad understanding of the new architectural 
changes of the database concerning the query optimizer. It explains the 
following:

* The architecture of the new query optimizer

* The new data access methods used by the optimizer

* The new Statistics Manager included in V5R2

* The feedback changes of the new query optimizer

* Some performance measurements


The Redbook is available at 
http://publib-b.boulder.ibm.com/Redbooks.nsf/RedpieceAbstracts/sg246598.html?Open.

==Kevin


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