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:
| |