[HBASE-3137] Optimize CAS operations in ZKAssign by being optimistic rather than always doing a sync()

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Incomplete
• Component/s: Zookeeper
• Assignee: Unassigned
• Reporter: Jonathan Gray
• Created: 21/Oct/10 00:31
• Updated: 12/Jun/22 00:30
• Resolved: 12/Jun/22 00:30

Description

HBASE-3136 introduces a fix to the CAS operations in ZKAssign by doing a call to ZK sync() before doing the operation.

This gives correct behavior but requires doing a sync every time, even if it isn't necessary. Instead, we should be optimistic and only do retries/syncing if necessary.

Issue Links

• relates to: HBASE-3136 Stale reads from ZK can break the atomic CAS operations we have in ZKAssign