PGA Memory and PGA_AGGREGATE_TARGET, is there Something Wrong with this Quote?

4 08 2010

August 4, 2010

I started reading the “Expert Oracle Database Architecture: Oracle Database 9i, 10g, and 11g Programming Techniques and Solutions” book cover-to-cover.  Very interesting book so far, and it appears that a lot of time was spent reworking the previous release of the book so that it targets Oracle Database 11g R2, while not losing the book’s usefulness for prior releases of Oracle Database.  On page 131 of the book I found an interesting quote that made me wonder… is there something wrong with this quote (roughly the same quote is found on page 125 of the first edition of the book)?

“… You may well have multiple work areas in your session for multiple queries, or more than one sort or hash operation in a single query, but each work area will be about 5 percent or less of the PGA_AGGREGATE_TARGET.”

Visit the above Google books links above for the quote’s context.

Is there something wrong with the above quote?  (Possible hint _SMM_MAX_SIZE.)