Page History

...

For non-source tasks that do not receive the direct trigger of the checkpoint, it will receive barriers from some channels, but may receive EndOfPartition from some other channels. In this case, the channel received by EndOfPartition would be viewed as receiving the corresponding barrier. Specifically, for aligned checkpoints, the channels received EndOfPartition would be viewed as aligned. For unaligned checkpoints, the buffers before the EndOfPartition message will be snapshotted.

...