xid() — PostgreSQL formatting function

xid(): convert xid8 to xid. PostgreSQL type conversion functions — signature, volatility, version applicability and an illustrative example.

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

Summary

xid is a PostgreSQL built-in function in the Type Conversion Functions group. PostgreSQL’s system catalog (pg_proc) describes it as: “convert xid8 to xid”.

Signature

xid(xid8) → xid

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: Type Conversion Functions
  • Kind: Function
  • Volatility: IMMUTABLE — Marked IMMUTABLE — it always returns the same result for the same arguments and can be used in indexes and other contexts that require immutability.
  • Returns: xid

Example

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

SELECT xid(NULL::xid8);

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

xid 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 — Type Conversion Functions.