Re: Memory Allocations




"Brian Peasland" <dba@xxxxxxxxxxxxxxxxxxx> wrote in message
news:46e744d7$0$15142$88260bb3@xxxxxxxxxxxxxxxxxxxx
Dereck L. Dietz wrote:
I was told by someone that the general rule of thumb for the initial
memory allocation in an Oracle instance was something like 40% for the
SGA and 60% for the PGA.

Anybody willing to comment on how accurate/inaccurate that statement was?

Thanks.

Personally, I've never used that rule of thumb. The sizes of the PGA and
SGA should be determined by your application and data usage patterns. Your
application and the way your users access the data may denote that a 2GB
SGA is appropriate. Servers with 4GB, 8GB, and 16GB of physical memory
(RAM) would arrive at entirely different estimates for the SGA using this
40% rule.

You can use rules of thumb similar to these as a starting point. But I
would expect that in short order, you would need to adjust your SGA and
PGA.

If you sized your instance by the rules you stated, 100% of the server's
physical memory would be tied up with just the Oracle instance!


HTH,
Brian


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Thanks. I realize it's just a starting point. Also, it's not for all the
server's memory - just the amount of memory which is going to be allocated
to the Oracle instance.


.



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