Ceilometer/AlarmEvaluatorJuno
Statistics over sliding windows
Two approaches to improve the alarm evaluator were discussed at the summit.
Map-reduce approach
Increment/decrement approach
Statistics where increments/decrements are possible:
- count,
- sum,
- average,
- stddev
Statistics with special implementation:
- min/max : needs O(log n) space (probably in DB), where n = window size
- percentile : classical statistics query
- cardinality : approximate algorithm, extremely efficient
Map-reduce approach covers all these statistics.
