RE: Oracle Shared Server Implementation

  • From: "Goulet, Richard" <Richard.Goulet@xxxxxxxxxxx>
  • To: "JBECKSTROM@xxxxxxxxx" <JBECKSTROM@xxxxxxxxx>, oracle-l-freelists <oracle-l@xxxxxxxxxxxxx>, oracle-db-l <oracle-db-l@xxxxxxxxxxxxxxxxxxxx>
  • Date: Mon, 1 Aug 2011 13:29:08 +0000

Jeff,

               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@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] 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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