Re: Which background process regulates amount of pga memory per session in 10g ? Thanks, rm.

On Mon, 05 Sep 2005 08:28:11 +0000, Jonathan Lewis wrote:

>
> I believe that it is CKPT that deals with co-coordinating
> PGA memory across sessions.

Now, that's is an interesting choice. Do you have any particular reason to believe that? Hans Forbrich has proven to me that there might not be any coordinator, just an area in SGA, so what makes you think that there is a coordinator and, if there is, why would you chose CKPT? CKPT was normally in charge of updating control files and datafile headers during the checkpoint processing.

>
> Individual sessions display their current workareas
> in v$sql_workarea_active, and processes display
> their PGA usage in v$process. These figures allow the
> background process to calculate values for V$pgastat,
> updating it every three seconds.
>
> One of the critical values in v$pgastat is the global memory
> bound (which starts life at _smm_max_size) that restricts
> the size of a single workarea in a session - and this is the
> figure that a session checks to restrict its memory demand
> at various stages in the lifetime of a workarea operation.

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