ReplicaFetcherManager

ReplicaFetcherManager is a manager of ReplicaFetcherThreads for ReplicaManager.

Figure 1. ReplicaFetcherManager

ReplicaFetcherManager uses num.replica.fetchers configuration property for the number of replica fetcher threads.

Tip	Enable `ALL` logging level for `kafka.server.ReplicaFetcherManager` logger to see what happens inside. Add the following line to `config/log4j.properties`: `log4j.logger.kafka.server.ReplicaFetcherManager=ALL` Refer to Logging.

Performance Metrics

As an AbstractFetcherManager, ReplicaFetcherManager is a KafkaMetricsGroup.

The performance metrics are registered in kafka.server:type=ReplicaFetcherManager group.

Figure 2. ReplicaFetcherManager in jconsole

Creating ReplicaFetcherManager Instance

ReplicaFetcherManager takes the following to be created:

KafkaConfig
ReplicaManager
Metrics
Time
Thread name prefix (undefined by default)
ReplicationQuotaManager

Creating ReplicaFetcherThread — `createFetcherThread` Method

createFetcherThread(
  fetcherId: Int,
  sourceBroker: BrokerEndPoint): ReplicaFetcherThread

Note	`createFetcherThread` is part of the AbstractFetcherManager contract to…FIXME.

createFetcherThread creates a ReplicaFetcherThread with the thread name (that uses the threadNamePrefix if defined, the given fetcherId and the id of the BrokerEndPoint) as follows:

[prefix]ReplicaFetcherThread-[fetcherId]-[sourceBrokerId]

`shutdown` Method

shutdown(): Unit

shutdown prints out the following INFO message to the logs:

shutting down

shutdown closeAllFetchers.

In the end, shutdown prints out the following INFO message to the logs:

shutdown completed

Note	`shutdown` is used when…FIXME

ReplicaFetcherManager