Critical Description
We found this issue when trying to issue multiple instances of the following multi-op concurrently
multi {
1. create sequential node /a-
2. create node /b
}
The expected result is that only the first multi-op request should success and the rest of request should fail because /b is already exist
However, the reported result is that the subsequence multi-op failed because of sequential node creation failed which is not possible.
Below is the return code for each sub-op when issuing 3 instances of the above multi-op asynchronously
1. ZOK, ZOK
2. ZOK, ZNODEEXISTS,
3. ZNODEEXISTS, ZRUNTIMEINCONSISTENCY,
When I added more debug log. The cause is that PrepRequestProcessor rollback outstandingChanges of the second multi-op incorrectly causing sequential node name generation to be incorrect. Below is the sequential node name generated by PrepRequestProcessor
1. create /a-0001
2. create /a-0003
3. create /a-0001
The bug is getPendingChanges() method. In failed to copied ChangeRecord for the parent node ("/"). So rollbackPendingChanges() cannot restore the right previous change record of the parent node when aborting the second multi-op
The impact of this bug is that sequential node creation on the same parent node may fail until the previous one is committed. I am not sure if there is other implication or not.