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Version: nightly

Overview

Introduction​

Flownode provides a simple streaming process (known as flow) ability to the database. Flownode manages flows which are tasks that receive data from the source and send data to the sink.

Flownode support both standalone and distributed mode. In standalone mode, Flownode runs in the same process as the database. In distributed mode, Flownode runs in a separate process and communicates with the database through the network.

Components​

A Flownode contains all the components needed for the streaming process of a flow. Here we list the vital parts:

  • A FlownodeManager for receiving inserts forwarded from the Frontend and sending back results for the flow's sink table.
  • A certain number of FlowWorker instances, each running in a separate thread. Currently for standalone mode, there is only one flow worker, but this may change in the future.
  • A Flow is a task that actively receives data from the source and sends data to the sink. It is managed by the FlownodeManager and run by a FlowWorker.