Shared Servers and Automatic Workarea Management in Oracle10g
In Oracle10g,the automatic PGA memory management mode applies to work areas allocated by both dedicated and shared Oracle database servers.
That means,under automatic PGA memory management mode,when sessions run SQL via shared server processes,SQL Work Areas will be allocated from PGA,rather than large pool like in oracle9i. SQL Work Areas is a runtime area dedicated for memory-intensive operators,sush as Sort-based operators (order by, group-by, rollup, window function), Hash-join,Bitmap merge,Bitmap create,etc.
Since less memory is allocated from large pool, shared pool latch will not have big contention under massive parallel sort&hash&bitmap operations by using automatic PGA memory management mode in shared server mode.
Yesterday I read an article from Pythian Group Blog,Shared Servers and Automatic Workarea Management.It impressed me.
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