[HDFS-17198] RBF: fix bug of getRepresentativeQuorum when records have same dateModified

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.4.0
• Fix Version/s: 3.4.0
• Component/s: rbf
• Labels: pull-request-available
• Target Version/s: 3.4.0
• Hadoop Flags: Reviewed
• Assignee: Jian Zhang
• Reporter: Jian Zhang
• Created: 18/Sep/23 04:01
• Updated: 28/Jan/24 01:27
• Resolved: 20/Sep/23 17:04

Description

Bug description

In the original implementation, when each router reports nn status at different times, the nn status is the status reported by majority routers, for example:
router1 -> nn0:active dateModified:1

router2 -> nn0:active dateModified:2

router3 -> nn0:active dateModified:3

router0 -> nn0:standby dateModified:4

Then, the status of nn0 is active, because majority routers report that nn0 is active.

If majority routers report nn status at the same time, for example:
(record1) router1 -> nn0:active dateModified:1

(record2) router2 -> nn0:active dateModified:1

(record3) router3 -> nn0:active dateModified:1

(record4) router0 -> nn0:standbydateModified:2

Then the state of nn0 is standby, but We expect the status of nn0 is active

This bug is because the above record is put into the Treeset in the method getRepresentativeQuorum. Since record1,2,3 have the same dateModified, there will only be one record in the final treeset of this method, so this method thinks that this nn is standby, because record4 newer

How to reproduce

Running my unit test testRegistrationMajorityQuorumEqDateModified, but using the original code

Issue Links

• links to: GitHub Pull Request #6096