If we want to see what the trend of the data is, then we can apply the .trend() function, which creates a plot for the trend using the regression algorithm. To explain the data trend, I am going to use the sum metric of the system.process.memory.size field of Metricbeat. So, for applying the trend to the preceding series, we need to apply the .trend() function in the expression, as follows:

.es(index=metricbeat*, metric=sum:system.process.memory.size ).label('system process memory size').trend()

After executing the preceding expression, we can get a trend plot showing the data trend based on the history. The following screenshot shows a plot that is showing the current trend for the series:

The preceding graph shows the trend of the data going up in the last 15 weeks. This trend can be created for any data series just by chaining the expression with the .trend() function.