[ZOOKEEPER-1483] Fix leader election recipe documentation

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.4.3
• Fix Version/s: 3.4.4, 3.5.0
• Component/s: documentation
• Assignee: Michi Mutsuzaki
• Reporter: Ankur Bansal
• Created: 11/Jun/12 21:09
• Updated: 14/Dec/12 22:11
• Resolved: 14/Sep/12 07:34

Description

The leader election recipe documentation suggest that to avoid the herd effect a client process volunteering for leadership via child znode [i] under the leader election path [/leader] must only watch the the SMALLEST znode [j] from a different client process such that [j < i].

This will NOT avoid the herd effect as many clients will end up watching the same znode[j] where j is the next-in-sequence number greater than the number of the current leader.

Specifically in Step 3 of the Election procedure here http://zookeeper.apache.org/doc/trunk/recipes.html#sc_leaderElection

This "where j is the SMALLEST sequence number" should be changed to this
"where j is the LARGEST sequence number"

Issue Links

• duplicates: ZOOKEEPER-1404 leader election pseudo code probably incorrect