Method BuildHybridRrfSql

Namespace

Qavren.Edge.VectorData

Assembly

Qavren.Edge.VectorData.dll

BuildHybridRrfSql(bool, bool)

The hybrid query: a vec0 KNN lane and an FTS5 bm25 lane, fused by reciprocal rank.

Both lanes rank ascending. FTS5's bm25() is the standard score multiplied by -1, so a better match is numerically lower, and vec0's distance is a distance. The hidden rank column is used rather than calling bm25(f), which SQLite's own docs say is faster.

The keyword lane says f."<fts table>" MATCH $keywords - the alias qualifying the table-named hidden column - and not the bare alias f MATCH $keywords. FTS5 gives every table a hidden column named after the table, and <x> MATCH <expr> is an ordinary comparison against a column, so a bare alias resolves as a column reference and SQLite answers no such column: f. Measured against SQLite 3.53.4 + FTS5 on 2026-09-11; spec 13.3's claim that the bare alias is the only spelling that parses is wrong in both directions, and the spec is the side that is being corrected.

The fused score is a similarity - higher is better - the opposite polarity to BuildKnnSql(bool, bool, bool)'s distance.

public string BuildHybridRrfSql(bool hasFilter, bool includeVectors)

Parameters

hasFilter bool

Emit the rowid pre-filter in BOTH lanes.

includeVectors bool

Emit both halves of the vector bracket: the LEFT JOIN and the projection.

Returns

string

The query.