Field guides for running Elasticsearch and OpenSearch well.
October 26, 2026 · QueryCrunch
es_rejected_execution_exception is backpressure, not a hardware verdict. How to read write threadpool stats, size bulk requests by bytes, cut the per-document cost with refresh_interval and mapping changes, spot merge-bound storage — and how to tell when the cluster genuinely does need more nodes.
Read moreOctober 19, 2026 · QueryCrunch
The answer quality of a RAG system is mostly a retrieval problem. Chunk sizes that match how people ask, the retrievers syntax for composing BM25 and kNN, a reranker on the top 50 rather than the top 500, and a judgment list so you can tell whether any of it helped.
Read moreOctober 12, 2026 · QueryCrunch
Mappings are mostly immutable, so every field type fix becomes a reindex. The alias indirection, dual-write and catch-up options, _reindex throttling that does not melt the cluster, and the verification step before you cut over.
Read moreOctober 5, 2026 · QueryCrunch
When a second region or a second cluster appears, CCS and CCR solve different problems and cost very differently. Connection modes, round-trip behavior, soft-delete retention leases, follower lag, and a two-region layout that keeps storage single-copy.
Read moreSeptember 28, 2026 · QueryCrunch
Most Elastic Stack and OpenSearch alerting starts as a threshold on a dashboard and ends as a channel nobody reads. How to pick rule types, size look-back windows against your ingest lag, use SLO burn rates instead of static thresholds, and measure whether a rule earns its page.
Read more