The events are stored in an in-memory queue with configurable max size. It’s ideal for flows that need higher throughput and are prepared to lose the staged data in the event of a agent failures. Required properties are in bold.
Property Name Default Description
type – The component type name, needs to be memory
capacity 100 The maximum number of events stored in the channel
transactionCapacity 100 The maximum number of events the channel will take from a source or give to a sink per transaction
keep-alive 3 Timeout in seconds for adding or removing an event
byteCapacityBufferPercentage 20 Defines the percent of buffer between byteCapacity and the estimated total size of all events in the channel, to account for data in headers. See below.
byteCapacity see description Maximum total bytes of memory allowed as a sum of all events in this channel. The implementation only counts the Event body, which is the reason for providing the byteCapacityBufferPercentage configuration parameter as well. Defaults to a computed value equal to 80% of the maximum memory available to the JVM (i.e. 80% of the -Xmx value passed on the command line). Note that if you have multiple memory channels on a single JVM, and they happen to hold the same physical events (i.e. if you are using a replicating channel selector from a single source) then those event sizes may be double-counted for channel byteCapacity purposes. Setting this value to 0 will cause this value to fall back to a hard internal limit of about 200 GB.byteCapacityBufferPercentage：用来确定byteCapacity的一个百分比参数，即我们定义的字节容量和实际事件容量的百分比，因为我们定义的字节容量主要考虑Event body，而忽略Event header，因此需要减去Event header部分的内存占用，可以认为该参数定义了Event header占了实际字节容量的百分比，默认20%；
byteCapacity：首先读取配置文件定义的byteCapacity，如果没有定义，则使用默认defaultByteCapacity，而defaultByteCapacity默认是JVM物理内存的80%（Runtime.getRuntime().maxMemory() * .80）；那么实际byteCapacity=定义的byteCapacity * (1- Event header百分比)/ byteCapacitySlotSize；byteCapacitySlotSize默认100，即计算百分比的一个系数。