Bug 813978 - Part 1/5: use multi-key indexes. r=sicking, ferjm
Bug 813978 - Part 2/5: rewrite filtering by only one condition
Bug 813978 - Part 3/5: rewrite filtering by mix of any two conditions
Bug 813978 - Part 4/5:
Bug 813978 - Part 5: test cases for mixed filter targets.