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Apache Solr

Summary

Apache Solr is the third supported engine, shipped in MVP2. It runs behind the same SearchAdapter Protocol as Elasticsearch and OpenSearch — one workflow, one schema, three engines.

Version support

Versions Status
9.x supported (shipped in MVP2)
10.x supported (shipped in MVP2)

The bundled local Solr runs in SolrCloud mode with embedded ZooKeeper and the LTR module loaded (SOLR_MODULES=ltr).

What RelyLoop tunes

RelyLoop's SolrAdapter tunes query-time parameters expressed through Solr's edismax query parser — field boosts (qf/pf), mm, tie, function queries (bf/boost), and phrase boosts — plus {!ltr} rescore parameters where you use Learning-to-Rank. As with the other engines, trials are scored with ir_measures, so the metric is comparable across all three.

UBI on Solr

RelyLoop reads the standardized UBI schema (ubi_queries + ubi_events) identically across all three engines, so UBI-derived judgment generation (shipped in MVP2) works on Solr from day one.

Live UBI capture vs. read-path

The live event-capture component (solr.UBIComponent) does not ship in the stock solr:10.0 / solr:9.x images — no module, no class, no ref-guide page. RelyLoop's capability probe reports ubi_component_present=false accurately. The demo synthesizes UBI events directly into those collections rather than capturing them live; the read path (and therefore judgment generation) is identical regardless of how the events were captured.

Gotchas

Local dev runs without security

Solr's default is no security.json, so the bundled local Solr's admin and query calls are unauthenticated — the same local-dev posture as ES and OpenSearch. The adapter's solr_basic / solr_apikey support exists for real operator clusters that enable auth.

See also