# Flownode

> Overview of Flownode, a component providing streaming process capabilities to the database, including its components and current limitations.

# Flownode

## 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.

There are two execution modes for a flow:
- **Streaming Mode**: The original mode where data is processed as it arrives.
- **Batching Mode**: A newer mode designed for continuous data aggregation. It periodically executes a user-defined SQL query over small, discrete time windows. All aggregation queries now use this mode. For more details, see the [Batching Mode Developer Guide](./batching_mode.md).

## Components

A `Flownode` contains all the components needed to execute a flow. The specific components involved depend on the execution mode (Streaming vs. Batching). At a high level, the key parts are:

- **Flow Manager**: A central component responsible for managing the lifecycle of all flows.
- **Task Executor**: The runtime environment where the flow logic is executed. In streaming mode, this is typically a `FlowWorker`; in batching mode, it's a `BatchingTask`.
- **Flow Task**: Represents a single, independent data flow, containing the logic for transforming data from a source to a sink.