tsmatchsel() — PostgreSQL full-text-search function

tsmatchsel(): restriction selectivity of tsvector @@ tsquery. PostgreSQL full text search functions — signature, volatility, version applicability and an illustrative example.

The Sev-1 Admin
The Sev-1 Admin  ·  2 min read

Summary

tsmatchsel is a PostgreSQL built-in function in the Full Text Search Functions group. PostgreSQL’s system catalog (pg_proc) describes it as: “restriction selectivity of tsvector @@ tsquery”.

Signature

tsmatchsel(internal, oid, internal, integer) → double precision

Argument and return types are taken from the pg_proc catalog; internal type names are shown using their readable SQL spellings (for example int4 is shown as integer). (Derived from the catalog — see the linked reference for the canonical documentation.)

Classification

  • Category: Full Text Search Functions
  • Kind: Function
  • Volatility: STABLE — Marked STABLE — within a single statement it returns a consistent result for the same arguments, but the result can change between statements.
  • Returns: double precision

Example

Illustrative form (replace placeholder values with your own data):

SELECT tsmatchsel(NULL::internal, 42, NULL::internal, 42);

The example above is illustrative and is meant to show calling syntax only; consult the linked PostgreSQL documentation for exact semantics, edge cases and accepted argument combinations.

Version applicability

tsmatchsel is present across the surveyed releases (PostgreSQL 15, 16, 17, 18, 19). On older major versions, behaviour may differ in detail — always check the documentation for the version you run.

Related & references

Reference: PostgreSQL documentation — Full Text Search Functions.