subscriptionsView

What an operator reads of the node's subscriptions, the built-in ones included, each by the group it runs in, and of the checkpoints its groups hold under names they no longer have:

• A subscription of a context's log (SubscriptionView.Source.LOG) stands in every partition its group saved a checkpoint of, read with one me.ahoo.wow.spi.subscription.CheckpointStore.list of the group. In a partition this node runs, its position is its live watermark, with the head sample read of the partition and whether the partition is paused or throttled.

• A subscription of a topic (SubscriptionView.Source.TOPIC: a context's command intake, another context's published topic) lists only the partitions this node runs that are paused or throttled.

• Its parked entries are sample's count (NodeSampler), null when the sample has none.

• The orphans are each log group's and each joined topic's (SubscriptionRuntime.orphans: an application's names, not Wow's own), their parked entries counted up to maxParked, as the sampler counts. A node registers its application's subscriptions as it starts, so it tells them only once it runs: before, every name would be one.

A store that fails fails the read (me.ahoo.wow.spi.StorageUnavailableException).