Why timelion .sum() is not working

[jerrychen (陈浩)]

env: es 6.2, kibana 6.2
I what to graph the total disk io bandwidth.
First,I get the graph group by ipaddr.

Then, when i do .sum(),it return nothing.

Finally,I add .abs() before .sum(),it works.

My questions:

1. Why .sum() in step 2 is not working?

2. I am not sure the result of .abs().sum() is right.

[spalger (Spencer Alger)]

I assume it's because some of your series have missing data for some periods, which breaks the .sum() function. If you use .fit() or .abs() then it will ensure that every bucket has a value and .sum() will work as intended.

[jerrychen (陈浩)]

What will the .fit() or .abs() return,if it is no data?

Is there any doc about example of all math functions?

[spalger (Spencer Alger)]

.fit() is configurable and returns different values based on the mode you choose. "carry" will reuse the most recent value when there is no data. "nearest" will do the same, except that it uses the nearest, not just the most recent, so sometimes it will use the next data point. "scale" will interpolate data points so that the gaps transition "smoothly" (if your data was [1, null, null, 4], "scale" would produce [1,2,3,4]).

.abs() is just going to fill in null points with 0 I believe, didn't realize it did that until reading your post though

The documentation for each function is visible in the autocomplete and the "help" tab, but most functions could use a bit more color.

[jerrychen (陈浩)]

The timelion "help" just list the keyword,I want to get the reference like your explaination.

Thinks for your help!