filter(<expression> [, <metric>|source=|tagk=<pointTagKey>])
Filters the expression to display only the time series that match the specified metric, source, or point tag. To filter by a particular source or point tag, specify
tagk=, respectively. You can specify only one filtering parameter per function call.
|expression||Expression that you want to filter.|
|metric|source=|tagk=||The metric, source or point tag to filter by.|
filter() function filters the expression to display only the time series that match the specified metric, source, or point tag. To filter by a particular source or point tag, specify
tagk=, respectively. Set
pointTagKey to the unique point tag key to filter by.
You can specify only one filtering parameter (metric, source, or point tag) per function call. To filter by multiple parameters, use a
filter() call for each parameter.
filter() is similar to
retainSeries(), but does not support matching a source tag.
Point Tag Filters
Use point tags to add extra dimensions to individual data values. While source tags are great for filtering your data to just the sources that are important to your use case, they do not store historical data. If your company uses a cloud-computing platform, then you might see instances constantly being re-provisioned as they are spun up and shut down. In those cases, historical data can be very important.
Point tags are tied to individual data values, and allow you to create queries based on historical data. Point tags are expressed as
<PointTagKey> = <PointTagValue>. The
PointTagValue are unique to each customer. For example, let’s say that source
app-1 is reporting data values for application
BLUE to metric
cpu.loadavg.1m. However the next day
app-1 is re-provisioned and is now reporting data values for application
RED. The data values reported by
app-1 can include a
app and a
blue. You could then construct the following query to only see data values for application
ts(“cpu.loadavg.1m”, source=“app-1” and app=“blue”)
The following example filters the disk space used metrics to show only the data for
app-10. The advantage of using
filter() is that it’s very clear that the filtering is going on; that helps other users understand your query.