Re: changing SYSTEM-tablespace to automatic segment-space management

On Fri, 11 Nov 2005 16:47:02 +0100, Moritz Klein wrote:

> Hello all,
> after my update from 10gR1 to 10gR2 went out smoothly I am faced with a
> info from OEM I am not really sure if I should take it or not. OEM says
> that my SYSTEM-tablespace is set to manual segment-space management
> which should be auto.

To change that is extremely simple: just re-run the create database statement with system tablespace having automatic segment space management. The trick with the automatic segment space management is that it handles free lists for you. That is good either if you have a RAC configuration or if you have extremely high insert rate, so that your objects might need more then a single free list rate. What is a free list? Free list is a list of blocks available for inserts. Oracle advises that no more then 30 transactions should use any single free list at any moment in time or there will be significant waiting time. So, if you have 300 users inserting in a table concurrently, you will need 10 free lists. Also, if your database is spread across more then a single instance, you should consider having free lists for each instance accessing your database.An ass managed tablespace will handle that for you. An excellent paper about ass managed tablespaces can be found at http://integrid.info. You were talking about the system tablespace. Do you have RAC or do you have a high insert rate into system tablespace?

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