This topic describes how to use maximum value detection functions to find the locally maximum value of time series data in a specified window.
ts_find_peaks
Function format:
* and h : nu2h05202.nu8 and m: NET  select ts_find_peaks(stamp, value, 30) from (select '("__time__"  ("__time__" % 10))' as stamp, avg(v) as value from log GROUP BY stamp order by stamp)
The following table lists the parameters of the function format.
Parameter  Description  Value 
x  The time sequence. Points in time are sorted in ascending order along the horizontal axis.  Each point in time is a Unix timestamp. Unit: seconds. 
y  The sequence of numeric data corresponding to each specified point in time.  N/A. 
winSize  The minimum length of the detection window.  The value of the parameter is of the long data type, ranging from 1 to the length of time series data. We recommend that you set this parameter to one tenth of the actual data length. 
Example:
The query statement is as follows:
* and h : nu2h05202.nu8 and m: NET  select ts_find_peaks(stamp, value, 30) from (select __time__  __time__ % 10 as stamp, avg(v) as value from log GROUP BY stamp order by stamp)
The following figure shows the output result.
The following table lists the display items.
Display item  Description  
Horizontal axis  unixtime  The timestamp of time series data. Unit: seconds. Example: 1537071480. 
Vertical axis  src  The raw data. Example: 1956092.7647745228. 
peak_flag  Indicates whether the numeric value at the time point is the maximum value. Valid values:
