+1 guo jiwei <[email protected]>于2026年8月18日 周二10:47写道：
> Hi dev, > > I'd like to propose PIP-492: Add subscription-level storage backlog age > metric. > > Pulsar currently exposes `pulsar_storage_backlog_age_seconds`, which > reports the > age of the oldest backlog message at the topic level. This is useful for > detecting consumer lag by time, but it does not show which subscription is > responsible for the backlog. For topics with multiple subscriptions, > different > subscriptions can have different latency expectations, so a topic-level > value > can lead to noisy alerts or extra manual investigation. > > This proposal adds a new Prometheus metric, > `pulsar_subscription_storage_backlog_age_seconds`, to expose the backlog > age per > persistent durable subscription. The existing topic-level metric remains > unchanged. The new value is also exposed through `SubscriptionStats` as a > best-effort field. > > Because this adds per-subscription computation and one potential time > series per > subscription, the proposal introduces a dedicated broker configuration, > `exposeSubscriptionBacklogAgeInPrometheus`, defaulting to `false`. > When disabled, > the broker skips the per-subscription backlog age computation. When > enabled, the > broker computes and caches the value, and the Prometheus metric is emitted > through the existing topic/subscription metrics path when topic-level > metrics > are enabled. > > Non-durable Reader subscriptions and non-persistent topics are > intentionally out > of scope for this PIP. > > Full proposal: https://github.com/apache/pulsar/pull/26362 > Implementation PR: https://github.com/apache/pulsar/pull/26313 > > > > Regards > Jiwei Guo (Tboy) >
