Dedicated vs. Oracle Database Tips by Donald Burleson. The Oracle multithreaded server MTS, later renamed "shared servers" was developed way-back in the days of Oracle7 when RAM was very expensive and RAM region sizes were severely limited by bit technology. Oracle shared servers are also inappropriate for ERP packages that spawn and hold database connections within the application server layer. Bobby Durrett notes that shared servers make sense in rare cases where you have a farm of web servers connecting to your Oracle database, a case where connection pooling makes sense. We have had some outages on the weekend caused by a sudden burst in web server generated database activity. In the past the CPU load would spike and log file sync commit waits would be 20 times slower and we would have to bounce the database and web servers to recover. Sunday we had a similar spike in database activity without having any sort of outage. There are also limitations to using the MTS. The Oracle 10g documentation indicates that session migration for BFILE datatypes in shared server multithreaded server mode is not supported.
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The server process is not shared by any other client. PMON registers information about dedicated server processes with the listener. This enables the listener to start a dedicated server process when a client request arrives and forward the request to it.
Enabling Session Multiplexing
Oracle Database creates server processes to handle the requests of user processes connected to an instance. A server process can be either of the following:. Your database is always enabled to allow dedicated server processes, but you must specifically configure and enable shared server by setting one or more initialization parameters. Figure , "Oracle Database Dedicated Server Processes" illustrates how dedicated server processes work. In this diagram two user processes are connected to the database through dedicated server processes.
Join Stack Overflow to learn, share knowledge, and build your career. Connect and share knowledge within a single location that is structured and easy to search. I have been using Oracle for many years, since Version 7. I had always understood shared server connections to be somewhat of an anachronism, for when you would try and shoehorn hundreds of connections into boxes with MBs of Ram and for modern servers was not an issue, particularly as you would expect most applications to be using connection pools anyway. I haven't seen anything other than dedicated server connections for years. I was surprised to see this line in the Administrators guide up until 12c. In general, it is better to be connected through a dispatcher and use a shared server process. Although it appears to have gone in more recent versions, with more discussion of database resident connection pooling.