Cross-Cluster Search Coordination Overhead
warningCross-cluster search queries can cause significant coordination overhead, network traffic, and timeout issues when remote clusters are slow or have high latency.
elasticsearch.search.query showing elevated latency with high elasticsearch.node.cluster.io and elasticsearch.transport.tx_size when cross-cluster search is active
Monitor cross-cluster search performance via search profiling and _remote/info API. Optimize: (1) Minimize data transferred - use size and fields parameters aggressively, (2) Use index patterns to limit remote shard count, (3) Implement skip_unavailable:true to avoid blocking on slow clusters, (4) Set appropriate timeouts for remote clusters, (5) Use minimize_roundtrips:true to reduce network hops. For frequently accessed remote data, consider replication or periodic snapshots to local cluster. Monitor network latency between clusters and ensure adequate bandwidth. Review elasticsearch.cluster.in_flight_fetch for concurrent remote operations.