Re: dynamically allocating chunks from shared memory

Hi,

On 08/09/2010 08:45 PM, Robert Haas wrote:
> Yeah, I think that's a real concern.  I think we need to distinguish
> memory needs from memory wants.  Ideally, we'd like our entire
> database to be cached in RAM.  But that may or may not be feasible, so
> we page what we can into shared_buffers and page out as necessary to
> make room for other things.  In contrast, the traditional malloc()
> approach doesn't give you much flexibility: if it returns NULL, you
> pretty much have to fail whatever operation you were trying to
> perform.  For some things, that's OK.  For other things, it's not.

Agreed, it's going to be a difficult compromise and it possibly is very 
hard to find a good one automatically. However, I doubt our current 
approach with hard limits between subsystems is the best compromise.

Regards

Markus Wanner