It does not work as advertised, in AIX either... I played with this in AIX 5L.
- Kirti --- "Hately, Mike (LogicaCMG)" <[EMAIL PROTECTED]> wrote: > Stephen, > > The documentation is pretty wooly regarding this issue but the way it seems > to be intended to work is this: > At startup Oracle will allocate an SGA sized as specified in the > sga_max_size parameter. This is to ensure that the system has enough memory > accomodate what you see as a maximum requirement for the SGA. > After it's allocated this and started the database it should deallocate any > memory it holds over and above that required to store the components of the > SGA. In some platforms/versions this deallocation doesn't occur. Solaris for > example behaves like this unless you move to version 8. > It's possible that your version of Tru64 has a similar limitation or that > you're seeing a bug. > To my mind though, Oracle Support's claim that this is expected behaviour is > a bit of a cop out. This is certainly not the way it was supposed to work. > The concept guide states the following: > > "The SGA can grow in response to a database administrator statement, up to > an operating system specified maximum and the SGA_MAX_SIZE specification." > > and > > "Oracle can start instances underconfigured and allow the instance to use > more memory by growing the SGA components, up to a maximum of SGA_MAX_SIZE" > > Both of these statements imply that the unused memory is supposed to be > released back to the operating system. > The way that this feature operates on your system it allows you to juggle > storage backwards and forwards between caches which is still useful but not > 'what it says on the box'. > > I'd ask Oracle under what cirtcumstances this is normal behaviour. It's not > the way the software is intended to work so maybe it's a platform > limitation. > > In order to give you a better idea of what Oracle thinks it's SGA is using > you can query the following views : > > - V$SGA_CURRENT_RESIZE_OPS: > Information about SGA resize operations that are currently in progress. > An operation can be a grow or a shrink of a dynamic SGA component. > > - V$SGA_RESIZE_OPS: > Information about the last 100 completed SGA resize operations. > This does not include any operations currently in progress. > > - V$SGA_DYNAMIC_COMPONENTS: Information about the dynamic components in > SGA. > This view summarizes information based on all completed SGA resize > operations since startup. > > - V$SGA_DYNAMIC_FREE_MEMORY: > Information about the amount of SGA memory available for future dynamic > SGA resize operations. > > > Hope this helps, > Mike Hately > > __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Kirtikumar Deshpande INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
