Maximum practical cache size

[Ruslan Zasukhin]

On 3/12/09 10:16 PM, "Matthew Jew" <mjew at icnc.com> wrote:

Hi Matthew, 
 
> I am using Valentina 4.0 ADK for C++ on Mac OS X.
> 
> On my deployment machine, I usually have a good amount of RAM (2 GB or
> 4 GB).
> Not many processes are running on the deployment machine, so there is
> often 1.5 GB of unused/inactive memory
> (according to both the Activity Monitor application and the "top"
> command.)
> 
> Is there a practical limit to what Valentina can use as a cache setting?

    1.5 Gb / 2 = 750   can be used as MAX cache size.

Because rest 750Mb yet can be used for other RAM staf
    * bitsets arraysets
    * join tables
    * ram tmp tables
    - so on

> I know more cache is (usually) better, but is there a point past which
> having too much allocated
> can be a detriment to performance?

Frankly saying we don't know such barrier for v2.0 +
In v1 such barrier was about 20-30MB.


> (I mean, aside from allocating so much to the Valentina application
> that the rest of the system
>   has insufficient RAM.)

> If we leave plenty of RAM for other processes, is there a point at
> which we begin to hurt Valentina's speed?
> (Due to the overhead of managing the contents of a gigantic DB cache.)

Penalty can be if OS start push out Valentina cache to disk,
Then load it back

 
> I currently have the cache set to 20 MB.
> 
> I was thinking of increasing it to 1,024 MB (1 GB).

Too much

Also .. What is DB size ?

If db size if 200MB  then cache in 200MB will eat the whole db :)


-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

[I feel the need: the need for speed]