On a new system 'ceilometer meter-list' replies within a few seconds. Once a few days of data have been collected 'ceilometer meter-list' slows to 10+ minutes to reply. This is true when using any SQL backend. During the query it appears there is an excessive amount of SQL happening.
This was tested on Ubuntu Precise using following packages:
ii ceilometer-api 2013.1-0ubuntu1~cloud ceilometer api service
ii ceilometer-collector 2013.1-0ubuntu1~cloud ceilometer collector service
ii ceilometer-common 2013.1-0ubuntu1~cloud ceilometer common files
ii python-ceilometer 2013.1-0ubuntu1~cloud ceilometer python libraries
ii python-ceilometerclient 1.0.0-0ubuntu1~cloud0 Client library for Openstack ceilometer server.
From what I am gathering.. at request time there is a large join.. which doesn't take that much time.. Then there are thousands of small select statements recursively looping through the joined data. This is highly ineffective and there is probability that the issue is exponential.