Retries

These metrics track the retries of failed requests via the :src:Retries module <com/twitter/finagle/service/Retries.scala>.

Requeues represent requests that were automatically retried by Finagle. Only failures which are known to be safe are eligible to be requeued. The number of retries allowed are controlled by a dynamic budget, :src:RetryBudget <com/twitter/finagle/service/RetryBudget.scala>.

For clients built using :src:ClientBuilder <com/twitter/finagle/builder/ClientBuilder.scala>, the retries stat represents retries handled by the configured :src:RetryPolicy <com/twitter/finagle/service/RetryPolicy.scala>. Note that application level failures are not included, which is particularly important for protocols that include exceptions, such as Thrift. The number of retries allowed is controlled by the same dynamic budget used for requeues.

Somewhat confusingly for clients created via ClientBuilder there are an additional set of metrics scoped to tries that come from StatsFilter. Those metrics represent logical requests, while the metrics below are for the physical requests, including the retries. You can replicate this behavior for clients built with the Stack API by wrapping the service with a StatsFilter scoped to tries.

retries A stat of the number of times requests are retried as per a policy defined by the RetryPolicy from a ClientBuilder.

retries/requeues A counter of the number of times requests are requeued. Failed requests which are eligible for requeues are failures which are known to be safe — see com.twitter.finagle.service.RetryPolicy.RetryableWriteException.

retries/requeues_per_request A stat of the number of times requests are requeued.

retries/budget A gauge of the currently available retry budget.

retries/budget_exhausted A counter of the number of times when the budget is exhausted.

retries/request_limit A counter of the number of times the limit of retry attempts for a logical request has been reached.

retries/not_open A counter of the number of times a request was deemed retryable but was not retried due to the underlying Service not having a status of Open.

retries/cannot_retry A counter of the number of times a request was deemed requeueable but was not requeued due to the underlying ServiceFactory not having a status of Open.