Tumbling Window

The Tumbling Window buffer groups messages into fixed-size, non-overlapping time windows. Every configured interval, all messages accumulated within the current window are emitted together as a single batch; each message belongs to exactly one window. An optional join configuration lets you run a SQL join across multiple input sources at emission time.

Configuration

Field	Type	Required	Default	Description
type	string	yes	—	tumbling_window
interval	duration	yes	—	Fixed duration of each window. When it elapses, all accumulated messages are emitted. Examples: 1ms, 1s, 1m, 1h.
join	object	no	—	Optional SQL join configuration applied to emitted batches.

join

Field	Type	Required	Default	Description
query	string	yes	—	SQL query joining batch data from different input sources.
value_field	string	no	—	Name of the binary field holding the message payload. Defaults to the engine default binary value field.
codec	object	yes	—	Codec used to decode message batches before joining.
thread_num	integer	no	—	Number of worker threads used for parallel decoding during the join.

The codec field is a CodecConfig object: a type string selecting the codec plus any codec-specific fields.

Examples

Basic Configuration

yaml

buffer:
  type: "tumbling_window"
  interval: "1s"

With Join Configuration

yaml

buffer:
  type: "tumbling_window"
  interval: "5s"
  join:
    query: "SELECT a.id, a.name, b.value FROM input1 a JOIN input2 b ON a.id = b.id"
    codec:
      type: "json"