Currently the RESTAPI doesn't include time stamps for the statistical data that it provides. For example, the CPU usage data is reported as follows:

  GET /hosts/{host:id}/statistics/{statistic:id}
  <statistic href="..." id="...">
    <name>cpu.current.user</name>
    <description>User CPU usage</description>
    <values type="DECIMAL">
      <value>
        <datum>53</datum>
      </value>
    </values>
    <type>GAUGE</type>
    <unit>PERCENT</unit>
  </statistic>

With this information it isn't possible to know exactly when the information was collected. For users of the RESTAPI that poll these statistics periodically this complicates calculation of accurate averages, or any other statistical measures.

The objective of this RFE is to add to the statistics a time stamp that reliably indicates when the data was collected:

  GET /hosts/{host:id}/statistics/{statistic:id}
  <statistic href="..." id="...">
    ...
    <values type="DECIMAL">
      <value>
        <datum>53</datum>
        <time>2015-09-17T19:34:30.892+02:00</time>
      </value>
    </values>
  </statistic>

Note that even if the objective is to add the time stamp at the RESTAPI level, the rest of the components of the system (engine and VDSM) may need to be modified as well.