A metric signature is the combination of metric name and its labels. When StatsD Exporter receives a metric, it registers it at a computed signature and reuses it until restart.
When a conflicting signature is encountered, StatsD Exporter will drop the metric. This can happen when a metric name stays the same but a label is renamed or added.
StatsD Exporter does not indicate which metric is in conflict, but does increment statsd_exporter_events_conflict_total.
For MediaWiki, we cannot guarantee that we will not add/rename/remove labels to any given metric once its in use. This has happened once already.
I see a couple things we could do:
- Link the StatsD Exporter lifecycle to the MediaWiki Deployment lifecycle (i.e Restart StatsD Exporter when scap does a deploy)
- Configure StatsD Exporter's ttl to something other than 0 (never expire)
- <your idea here>