document metrics buffer and InfluxDB batching
concourse/concourse#3937
@@ -4,7 +4,7 @@ There is a new [container placement strategy](https://concourse-ci.org/container
There is also an optional 'max active tasks per worker' configuration. If this is set to a positive integer, you will see the following behaviour: If all workers are at their active task limit, you will see the message `All workers are busy at the moment, please stand-by.` and the scheduler will re-try a minute later. This pattern will repeat each minute indefinitely, until a worker is available.
-Thanks to @aledeganopix4d for all their hard work on this feature! #4118, #4148, #4208, #4277, #4142, #4221, #4293
+Thanks to @aledeganopix4d for all their hard work on this feature! #4118, #4148, #4208, #4277, #4142, #4221, #4293, #4161
#### <sub><sup><a name="v550-note-2" href="#v550-note-2">:link:</a></sup></sub> feature
@@ -18,3 +18,11 @@ PLACEHOLDER: Super admin #4238, first steps
We noticed after #4058 (where build steps are collapsed by default) that it wasn't very easy to see failing steps.
Now a failing step has a red border around its header, an erroring step has an orange border, and a running step has a yellow border. #4164, #4250
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+#### <sub><sup><a name="v550-note-5" href="#v550-note-5">:link:</a></sup></sub> feature
+
+On particularly busy clusters, users have observed [metrics events](https://github.com/concourse/concourse/issues/3674) [being dropped](https://github.com/concourse/concourse/issues/3769) due to a full queue #3937. @rudolfv added a configurable buffer size for metrics emission, regardless of your configured emitter. This should allow operators to trade memory pressure on the web nodes for reliability of metric transmission.
+
+#### <sub><sup><a name="v550-note-6" href="#v550-note-6">:link:</a></sup></sub> feature
+
+@rudolfv also added some features for the special case of InfluxDB metrics. To decrease the request load on InfluxDB, you can configure the number of events to batch into a single InfluxDB request, or you can specify a hardcoded interval at which to emit events, regardless of how many have accumulated #3937.
