Run this 20 times in my host, everything seems OK:

for i in `seq 1 20`; do
    ./gradlew :iceberg-flink:iceberg-flink-1.14_2.12:test --tests "org.apache.iceberg.flink.TestFlinkTableSink"
    if [ ! $? -eq 0 ] ; then
        exit 1
    fi
done

@openinx I have run the test hundreds of times locally in a test loop like you did before and was never able to reproduce it.

Think again about the root cause that we discussed in the issue where we may miss the notifyCheckpointComplete callback. As a result, two checkpoint cycles got squashed into one Iceberg commit and hence have 2 files for a partition in one Iceberg commit.

I misunderstood the PR earlier. Looks like the change is to make sure we have one checkpoint cycle for all rows to bypass the potential problem from multiple checkpoint cycles.

@stevenzwu The root cause is : Previous design could not guarantee that a single checkpoint could commit all rows to a given transaction. Here is another example. That's why we are now trying to guarantee this in this PR.

The new description looks good to me if you think it's more clear.

@openinx looks good. can you merge this? should be safe.

Thanks for fixing the flaky test, @openinx!