[SOLR-8980] Source cluster in CDCR setup should create clients for target cluster lazily

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 6.0
• Fix Version/s: 6.2, 7.0
• Component/s: CDCR, SolrCloud
• Assignee: Unassigned
• Reporter: Shalin Shekhar Mangar
• Created: 13/Apr/16 19:16
• Updated: 28/Oct/20 20:37
• Resolved: 28/Oct/20 20:37

Description

CdcrReplicatorManager currently eagerly creates a CloudSolrClient for the target cluster on each and every node of the source cluster. This is wasteful and causes a ZkStateReader and this a ZK connection to the target ZK servers. This is also why the CDCR page in the reference guide recommends increasing the maxClientCnxns setting in Zookeeper to keep up with the large number of connections maintained by the nodes in the source cluster.

Source cluster in CDCR setup should create clients for target cluster only on the leader nodes and that too lazily.