Error sending data to influxdb

[jonboydell-massive]

Hi,

When I'm running a load test against a URL (GET) with a query parameter that constantly changes I eventually get the following error:

time="2019-05-02T10:08:41Z" level=error msg="InfluxDB: Couldn't write stats" error="{"error":"partial write: max-values-per-tag limit exceeded (100027/100000): measurement=\"http_reqs\" tag=\"name\" value=\"https://some/url/here?param=ADNSADSADSADSADSA\\\" dropped=648"}\n"

It seems though k6 is sending the whole URL as the name tag (including query string params), and Influx soon bursts it's max-values-per-tag limit. I have changed this in InfluxDB to be unlimited. But how do I get k6 to use a more likely value for the name tag?

[na--]

Hi @jonboydell-massive, take a look at this part of the k6 docs about how you can customize the name tag to be less variable: https://docs.k6.io/docs/http-requests#section-aggregating-results-for-http-requests

If you don't want to manually modify the name tags everywhere, which, as you've seen, by default are the same as the url tags, you have two other options. You can make k6 emit the name metric tag as an InfluxDB field (which isn't indexed and is what we do for url by default) instead of a tag (which is indexed). You can do that via the INFLUXDB_TAGS_AS_FIELDS environment variable. More info here and here.

Or you can disable the name system tag altogether, by running k6 with something like k6 run --system-tags proto,subproto,status,method,url,group,check,error,error_code,tls_version script.js. Unfortunately due to open bugs you currently can't specify the system tags via an environment variable or a JS option 😞