🔧 Reciprocal Rank Fusion on free Elasticsearch: licensing, workarounds, and the OpenSearch alternative

Reciprocal Rank Fusion (RRF) on Elasticsearch is gated to the Enterprise tier. On the Basic/free tier, querying with the rrf retriever returns a 403:



{
"error": {
"root_cause": [
{
"type": "security_exception",
"reason": "current license is non-compliant for [Reciprocal Rank Fusion (RRF)]",
...