Difference between revisions of "User:Gibi"
| Line 4: | Line 4: | ||
* fact1: "instance" meter reports 1 if the instance is _allocated_ regardless of the state of the instance | * fact1: "instance" meter reports 1 if the instance is _allocated_ regardless of the state of the instance | ||
| − | * fact2: ceilometer does not have | + | * fact2: ceilometer does not have samples with counter_volume 0 for deleted instances obviously |
* fact3: the state of the instance is not part of the metadata of the "instance" sample | * fact3: the state of the instance is not part of the metadata of the "instance" sample | ||
Revision as of 15:46, 24 January 2014
Horizon instance statistic query: pastebin horizon pdf
- fact1: "instance" meter reports 1 if the instance is _allocated_ regardless of the state of the instance
- fact2: ceilometer does not have samples with counter_volume 0 for deleted instances obviously
- fact3: the state of the instance is not part of the metadata of the "instance" sample
Problem 1
So first you want to calculate avg(counter_volume) grouped by resource_id then make a sum(counter_volume) grouped by project_id. The avg(counter_volume) will produce invalid result if we have 6 measurement in an hour but the instance was running only half of the time, as we will have only 3 samples instead of 6 so the avg will be 1 instead of 1/2 due to fact2. If it is not a problem to get 1 instead of 1/2 for this case then you can use distinct instead of avg.
Problem 2
Your query with two group bys cannot be expressed in one SELECT statement. We have to translate the first avg (or distinct) step to a subquery of the second step. Our original idea for complex query statistic will allow multiple group bys but we haven't planned to allow such group bys that needs subqueries.
