pub const BARRIER_CONTROL_TYPE: i16 = 1000;Expand description
Control-record type of a krabka barrier marker.
Kafka assigns the control-record types 0 to 6: ABORT, COMMIT,
LEADER_CHANGE, SNAPSHOT_HEADER, SNAPSHOT_FOOTER, KRAFT_VERSION, and
VOTERS. The value 1000 starts a krabka-private range that Kafka cannot
reach by normal growth. krabka-raft uses the same convention for its
private api keys at 1003 and 1004.
A barrier marker is a control batch with one record. The record key holds
this type. The batch sets producer_id to -1, it sets producer_epoch to
-1, and it clears the transactional attribute bit. The log keeps no
transaction state and no producer state for such a batch. Kafka’s
ControlRecordType.parse reports an unknown type for the value 1000 and
skips the batch, so a JVM consumer never sees the record.
The broker builds the marker batch and the log classifies it. Both read this one constant.