OpenTSDB/opentsdb — pull request #357 by jesse5e (2014-07-03 00:04:31+00:00)
Title: Downsample before and after aggregation.

Supported downsampling aggregated results.
- Optional pre-downsampling query param is applied to the downsampling before
aggregation. The query parameters should end with "-pre" like "1h-avg-pre".
The default pre-downsampling could be applied if not specified.
- Optional post-downsampling query param is applied to the downsampling after
aggregation. It uses the existing downsampling query param syntax.
No post-downsampling will happen if not specified.
- The 0 second downsampling interval turns off the corresponding downsampling
explicitly.
- A query to aggregate CPU metrics of the last hour with 10s
pre-downsampling and 1 hour post-downsampling would be like:
"/api/query?start=1h-ago&m=sum:10s-avg-pre:1h-avg:rate:sys.cpu.0"