[HBASE-24720] Meta replicas not cleaned when disabled

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha-1, 2.3.0, 2.4.0, 2.2.5
• Fix Version/s: 3.0.0-alpha-1, 2.3.1, 2.4.0, 2.2.6
• Component/s: read replicas
• Assignee: Szabolcs Bukros
• Reporter: Szabolcs Bukros
• Created: 13/Jul/20 12:35
• Updated: 15/Jul/20 12:17
• Resolved: 14/Jul/20 17:17

Description

The assignMetaReplicas method works kinda like this:

void assignMetaReplicas(){
if (numReplicas <= 1) return;

//create if needed then assign meta replicas

unassignExcessMetaReplica(numReplicas);
}

Now this unassignExcessMetaReplica method is the one that gets rid of the replicas we no longer need. It closes them and deletes their zNode.  Unfortunately this only happens if we decreased the replica number. If we disabled it, by setting the replica number to 1 assignMetaReplicas returns instantly without cleaning up the no longer needed replicas resulting in replicas lingering around.

Issue Links

• Is contained by: HBASE-24554 Improve/stable read replica
• links to: GitHub Pull Request #2057