feature → setting ttl to clean up old metrics

[xamaterasux]

Hello,

Pushing metrics from batch scripts makes memory (RSS) increase over time. Could it be created a way to clean these metrics after a defined time (ttl) instead of getting this service restarted to free this memory?

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I've seen in the old project they had the idea of implementing so:

• Metrics never being cleaned up generates Memory and CPU performance issues weaveworks/prom-aggregation-gateway#44 (leads to the next one)
• [FEAT] Adding TTL to cleanup old metrics weaveworks/prom-aggregation-gateway#61

Inspecting metrics/aggregate.go I see a function:

44 func SetTTLMetricTime(duration *time.Duration) aggregateOptionsFunc {
 45     return func(a *Aggregate) {
 46         a.options.metricTTLDuration = duration
 47     }
 48 }

I think this is not being used, but I also don't know if this could be used. At the begining I thought I could set a value for this, but after searching for this function over the files I could not find a place where it was being used.

Thank you!