[Hawkular-dev] [Metrics] Unified query support brainstorming

[Thomas Segismont]

Hi everyone,

Right now, when you query data in Metrics, you can, given a time range:
- get raw data
- get raw data having some tags
- get a "bucketed" view of raw data with on-the fly aggregates
- get periods for which a condition on the value holds true

But you can't mix these capabilities.

For example, you can't ask for periods where the avg of a gauge, 
computed over 1 min buckets, is greater than a threshold.

It's not possible either to express AND/OR in tags or condition queries.

Searching by tags is useful, but users have to tag data manually (unless 
the collector adds some predefined tags). It would be useful to be able 
to operate on data coming from different metrics having similar names: 
like tell me the average cpu usage over all my web hosts, provided the 
metrics are _webhost*.cpu.usage_

When aggregating data, users should able to provide the name of the 
function, be it a builtin or user defined function.

Last but not least, when rollups will be implemented, users should 
probably not have to care about where the data is stored,if they ask for 
the 1-month average of a metric over the past year, or the 30-seconds 
average over the past five minutes (think about the UI zooming graphs).

The examples are not completely fabricated, it's feedback I got while 
presenting Hawkular. I understood Stefan heard similar comments during 
Summit.

I'm starting this thread to gather inputs so that we can build a 
powerful, unified query API. Feel free to provide more use cases and/or 
ideas for implementation.

Thanks!
Thomas