Type Members

1.  trait FetchStrategy extends AnyRef

   A fetch strategy determined which stream are allowed to fetch data in the next poll.

2.  final case class ManyPartitionsQueueSizeBasedFetchStrategy(maxPartitionQueueSize: Int = 1024, maxTotalQueueSize: Int = 20480) extends FetchStrategy with Product with Serializable

   A fetch strategy that allows a stream to fetch data when its queue size is at or below maxPartitionQueueSize, as long as the total queue size is at or below maxTotalQueueSize.

   A fetch strategy that allows a stream to fetch data when its queue size is at or below maxPartitionQueueSize, as long as the total queue size is at or below maxTotalQueueSize. This strategy is suitable when QueueSizeBasedFetchStrategy requires too much heap space, particularly when a lot of partitions are being consumed.

   maxPartitionQueueSize

   Maximum number of records to be buffered per partition. This buffer improves throughput and supports varying downstream message processing time, while maintaining some backpressure. Low values effectively disable prefetching in favour of low memory consumption. Large values leave it up to maxTotalQueueSize parameter to backpressure only over the buffers of all partitions together. The number of records that are fetched on every poll is controlled by the max.poll.records setting, the number of records fetched for every partition is somewhere between 0 and max.poll.records. The default value for this parameter is 2 * the default max.poll.records of 500, rounded to the nearest power of 2.

   maxTotalQueueSize

   Maximum number of records to be buffered over all partitions together. This can be used to limit memory usage when consuming a large number of partitions. When multiple streams are eligible for pre-fetching (because their queue size is below maxPartitionQueueSize), but together they exceed maxTotalQueueSize, then every call a random set of eligible streams is selected that stays below maxTotalQueueSize. The randomization ensures fairness and prevents read-starvation for streams at the end of the list. The default value is 20 * the default for maxPartitionQueueSize, allowing approximately 20 partitions to do pre-fetching in each poll.

3.  final case class QueueSizeBasedFetchStrategy(partitionPreFetchBufferLimit: Int = 1024) extends FetchStrategy with Product with Serializable

   A fetch strategy that allows a stream to fetch data when its queue size is at or below partitionPreFetchBufferLimit.

   A fetch strategy that allows a stream to fetch data when its queue size is at or below partitionPreFetchBufferLimit.

   partitionPreFetchBufferLimit

   The queue size at or below which more records are fetched and buffered (per partition). This buffer improves throughput and supports varying downstream message processing time, while maintaining some backpressure. Large values effectively disable backpressure at the cost of high memory usage, low values will effectively disable prefetching in favor of low memory consumption. The number of records that are fetched on every poll is controlled by the max.poll.records setting, the number of records fetched for every partition is somewhere between 0 and max.poll.records. The default value for this parameter is 2 * the default max.poll.records of 500, rounded to the nearest power of 2. The value 0 disables pre-fetching.