A checkpoint is completed when the nth the checkpoint barrier crosses the
last operator.
When we trigger a savepoint manually, which checkpoint barrier is
considered.
Is it the next checkpoint barrier(next relative to the last barrier that was
considered to create the last checkpoint or savepoint) that the job will
wait to cross the last operator create a savepoint.
I think I didn't make myself clear. Sorry.
What I want to know is, when we trigger the savepoint, which checkpoint
barrier will it consider to trigger the savepoint.