On 25/01/11 9:42 PM, André Rothe wrote:
Hello,
currently I try to understand the Cayenne design and implementation. Can you
explain, how you limit the number of objects, which are inside the cache? On an
application with a huge number of data rows, the most important point is the
size of the used memory for the object cache.
If you want more sophisticated caching, you might want to look at oscache or
other pluggable options for Cayenne. There is a section about that in the
manual.
As I have understand, Cayenne tracks the state of the object, so it is only
possible to remove transient objects from the cache. Is it possible to remove
the data of (e.g. committed) objects and hold only the id to save memory?
Yes, you can fetch data using paged queries. In that case the objects (well,
most of them) are hollow, meaning that they hold just the id. This is not only
good for memory usage, but also much faster across the network especially for
ROP. You can't make an object hollow once you already have it in memory, but
you can fetch them as hollow in the first place which is usually what you want
to do. It is not uncommon to see an order of magnitude improvement in memory
usage and performance with a reasonably large query result.
I have moved this thread to the correct place: on the user list. Please reply
there and drop dev@ from the cc list.
Ari
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Aristedes Maniatis
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