[storm] Limit cache size by memory usage?

[James Henstridge]

On Wed, Aug 5, 2009 at 3:30 PM, Stuart
Bishop<stuart.bishop at canonical.com> wrote:
>> Note that a larger cache isn't always going to be better: some
>> operations scan over the list of alive objects (e.g ResultSet.set), so
>> keeping more objects alive could slow those operations down.  If you
>> end up caching objects that never get used again, then you'd probably
>> be better off with a smaller cache.
>
> I wasn't aware of that. That would certainly screw up using an external
> cache like memcached.

As Gustavo said, memcached is really only useful at a higher layer:
you'd usually use it to cache information that will be valid over
multiple transactions, and has a measurable cost separate from object
instantiation.  You might even be caching fully rendered views that
comprise parts of the page here.

Storm's current cache really only there to (a) avoid refetching rows
within a transaction and (b) avoiding the need to instantiate objects.
 It has quite a different scope, so it probably isn't useful to
consider memcached at that level.

James.