Search Tuning & Relevance - Opensolr Drupal Docs

Search Tuning

The Search Tuning tab (/admin/config/search/opensolr/tuning) lets you fine-tune how search results are ranked.

💡 Optional!

The defaults work well for most sites. Only change these if you want to tweak how results are ranked or if you're getting unexpected search behavior.

Search Tuning showing Lexical Weight slider set to 1.00, and Field Weights inputs for Title, Description, URI, and Text — Lexical balance & field weights

Minimum Match presets (Flexible, Balanced, Strict, Custom), Search Mode radio buttons (Union, KW Required, Meaning Required, Intersection), and Vector Candidate Pool slider — Minimum match & search mode

Vector Candidate Pool topK slider, Result Quality Threshold slider from More Results to Stricter Match at 0.50, and red Reset All to Defaults button — Quality threshold & reset

Semantic vs. Lexical Balance

This slider controls the balance between two types of search:

Lexical (keyword) search — matches exact words in your content. "Drupal hosting" matches pages containing those exact words.
Semantic (vector) search — understands meaning. "Drupal hosting" also matches pages about "CMS cloud deployment" because the meaning is similar.

The slider goes from 10 (mostly semantic) to 100 (mostly keyword). Default is somewhere in the middle.

Slide left (more semantic)

Better for natural language questions ("how do I set up search on my site?"). Results match by meaning, not just keywords.

Slide right (more keyword)

Better for exact lookups ("search_api_solr module"). Results must contain the actual words typed.

Field Weights

These control how much each part of a page contributes to its relevance score:

Title — weight for the page title. Higher = title matches rank higher.
Description — weight for meta descriptions.
URI — weight for the page URL.
Text — weight for the full body text.

Minimum Match

Controls how many of the search terms must appear in a result for it to be included.

Flexible

Show more results, even if not all search words match. Good for broad discovery.

Balanced (recommended)

Most words must match. Good balance between completeness and precision.

Strict

Almost all words must match. Fewer results but more precise.

Custom

Enter your own Solr mm syntax for full control.

Search Mode

Controls how keyword and semantic signals are combined. Only affects vector-enabled indexes.

Union (default) — broadest. A result matches if keywords OR meaning matches.
Keywords Required — keywords must match, semantic adds extra boost.
Meaning Required — semantic match required, keywords add extra boost.
Intersection — most restrictive. Both keywords AND meaning must match.

Vector Candidate Pool

A slider from 10 to 1000 controlling how many vector candidates are considered before final ranking. Default: 500. Leave at 500 unless you notice search speed issues or missing results.

Result Quality Threshold

A slider from 0 to 100 setting the minimum relevance score. Lower = more results (including less relevant). Higher = fewer, more precise results. Start low and increase only if seeing too many irrelevant results.