I guess there's two answers, depending on what to sum:
to sum two series, you need to use the
.sum() function from Timelion. See https://github.com/elastic/timelion/blob/master/FUNCTIONS.md#sum.
it'd be something like
If summing series is not what you want, you may want to use a scripted-field instead. This will allow you to create a script that sums the two fields. See https://www.elastic.co/guide/en/kibana/current/scripted-fields.html for details.
e.g. suppose we create this scripted field
and call it
You can then use it in your timelion expression