RE: Oracle Shared Server Implementation

               Is there a reason for Shared Server. Good question and one that should be answered on a case by case basis. I use it on a number of instances where we have between 1 and 2 K sessions at any time and 99% of them are idle 80% of the time. (web based Hibernate app that just wants to stay connected. It also gets around a firewall issue with ports.) Otherwise I do prefer dedicated mainly because it's easier to set up. As for bugs, Dispatchers have limits especially with the number of sessions they can safely handle which is OS specific. Don't let them get to 50% of that limit. Second they do become a bottleneck because if their sending data to one session they can't to a second at the same time. Large reports can cause problems. Lastly a "slow" performing query can get to be harder to troubleshoot, especially if all your servers are busy. And be ready for out of memory issues as the SS pga resides in the shared pool. But for web based, mega connection apps that run fairly simple queries and are idle most of the time they can be a life saver. Small pool I realize, but don't through it out of the tool box. OH, BTW they do have one more benefit, shorter login times. We have a voice app that needs to connect to the database before replying with its hello message. Dedicated causes problems when the db server is busy (backup times in particular). Shared solves that one too.

Richard Goulet
Senior Oracle DBA/Na Team Leader

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Jeffrey Beckstrom Sent: Monday, August 01, 2011 8:22 AM
To: oracle-l-freelists; oracle-db-l
Subject: Oracle Shared Server Implementation

When we were on 32-bit hardware, for one of our databases we had to implement shared servers due to hitting the 32-bit memory limit. Since that time, we have migrated all of our systems to 64-bit hardware. My question is, on 64-bit hardware is there ever a need for shared servers?

Jeffrey Beckstrom
Database Administrator
Greater Cleveland Regional Transit Authority Information Systems
1240 W. 6th Street
Cleveland, Ohio 44113

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