fsub

Input Stack:
ts2: TimeSeriesExpr
ts1: TimeSeriesExpr
Output Stack:
(ts1 - ts2): TimeSeriesExpr
 

Floating point subtraction operator. Compute a new time series where each interval has the value (a - b) where a and b are the corresponding intervals in the input time series.

:fsub 1.0 0.0 1.0 NaN NaN
Input 1 2.0 0.0 1.0 1.0 NaN
Input 2 1.0 0.0 0.0 NaN NaN

Note in many cases NaN will appear in data, e.g., if a node was brought up and started reporting in the middle of the time window for the graph. This can lead to confusing behavior if added to a line that does have data as the result will be NaN. Use the sub operator to treat NaN values as zero for combining with other time series.

Example subtracting a constant:

BeforeAfter
name,sps,:eq
name,sps,:eq,
30000,:fsub

Example subtracting two series:

BeforeAfter
name,requestLatency,:eq,
:sum,
name,requestsPerSecond,:eq,
:max,
(,name,),:by
name,requestLatency,:eq,
:sum,
name,requestsPerSecond,:eq,
:max,
(,name,),:by,
:fsub