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vector_similarity

Enterprise scalar function reference.

Function Snapshot

Field Value
Function vector_similarity
Category Vector
Scope Scalar expression
Discovery SELECT * FROM pg_catalog.pg_proc WHERE proname = 'vector_similarity';

Purpose

Computes similarity score between vectors using the column default or explicit similarity override.

Syntax

SELECT vector_similarity(
  [0.1, 0.2, 0.3]::float_vector(3),
  [0.2, 0.1, 0.4]::float_vector(3)
);

Parameters

  • left_vector, right_vector: vectors with identical dimensions.
  • Optional similarity: literal, non-null override; must match column similarity when used against indexed vectors.

Returns

  • Returns numeric similarity score (double precision).

Null and Error Behavior

  • Similarity override must be a non-null literal string.
  • Override mismatch with column-declared similarity fails at planning.

Operational Notes

  • Prefer relying on column-declared similarity unless an explicit literal override is required.
  • Validate overload details in-cluster with pg_catalog.pg_proc and pg_get_function_result(oid).

Cross-References