Whilst developing the prototype image creation GUI I added some extra entries to the cache which increase it's size http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=a13304e1c6500db95823961a5a34849db46037e3 These entries, whilst essential for the image creation GUI, are useless overhead for all other (current) interfaces. A good feature for the Yocto 1.1 development cycle would be to allow UI's to request additional data be stored in the cache, and disable these entries by default.
Some ideas from IRC discussion: 16:36 < RP__> kergoth`, incandescant: One idea I'm toying with is having the cache be UI specific which would then handle a certain class of problems 16:44 < kergoth`> I thought about that too, or index the cache by the structure of the cached data in some way
Liping created a series of patches for this work which have been merged into the Poky and BitBake repositories. The key commit in the upstream repository is: http://git.openembedded.org/cgit.cgi/bitbake/commit/?id=077657e50ad032c0fa876bf54e9802af2686e0fb
This works and is in use by the hob 'image creator' BitBake UI.