[SOLR-8696] Start the Overseer before actions that need the overseer on init and when reconnecting after zk expiration and improve init logic.

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 5.4.1
• Fix Version/s: 6.0
• Component/s: SolrCloud
• Labels: patch performance solrcloud startup
• Assignee: Mark Miller
• Reporter: Scott Blum
• Created: 18/Feb/16 19:37
• Updated: 02/Oct/19 17:24
• Resolved: 29/Feb/16 21:39

Description

ZkController.publishAndWaitForDownStates() occurs before overseer election. That means if there is currently no overseer, there is ironically no one to actually service the down state changes it's waiting on. This particularly affects a single-node cluster such as you might run locally for development.

Additionally, we're doing an unnecessary ZkStateReader forced refresh on all Overseer operations. This isn't necessary because ZkStateReader keeps itself up to date.

Issue Links

• is cloned by: SOLR-8722 Don't force a full ZkStateReader refresh on every Overseer operation