The catalog pg_proc stores information about functions (or procedures). See CREATE FUNCTION and Section 35.3 for more information.

The table contains data for aggregate functions as well as plain functions. If proisagg is true, there should be a matching row in pg_aggregate .

Table 49-37. pg_proc Columns

Name Type References Description
oid oid Row identifier (hidden attribute; must be explicitly selected)
proname name Name of the function
pronamespace oid pg_namespace .oid The OID of the namespace that contains this function
proowner oid pg_authid .oid Owner of the function
prolang oid pg_language .oid Implementation language or call interface of this function
procost float4 Estimated execution cost (in units of cpu_operator_cost ); if proretset , this is cost per row returned
prorows float4 Estimated number of result rows (zero if not proretset )
provariadic oid pg_type .oid Data type of the variadic array parameter's elements, or zero if the function does not have a variadic parameter
protransform regproc pg_proc .oid Calls to this function can be simplified by this other function (see Section 35.9.11 )
proisagg bool Function is an aggregate function
proiswindow bool Function is a window function
prosecdef bool Function is a security definer (i.e., a "setuid" function)
proleakproof bool The function has no side effects. No information about the arguments is conveyed except via the return value. Any function that might throw an error depending on the values of its arguments is not leak-proof.
proisstrict bool Function returns null if any call argument is null. In that case the function won't actually be called at all. Functions that are not "strict" must be prepared to handle null inputs.
proretset bool Function returns a set (i.e., multiple values of the specified data type)
provolatile char provolatile tells whether the function's result depends only on its input arguments, or is affected by outside factors. It is i for "immutable" functions, which always deliver the same result for the same inputs. It is s for "stable" functions, whose results (for fixed inputs) do not change within a scan. It is v for "volatile" functions, whose results might change at any time. (Use v also for functions with side-effects, so that calls to them cannot get optimized away.)
pronargs int2 Number of input arguments
pronargdefaults int2 Number of arguments that have defaults
prorettype oid pg_type .oid Data type of the return value
proargtypes oidvector pg_type .oid An array with the data types of the function arguments. This includes only input arguments (including INOUT and VARIADIC arguments), and thus represents the call signature of the function.
proallargtypes oid[] pg_type .oid An array with the data types of the function arguments. This includes all arguments (including OUT and INOUT arguments); however, if all the arguments are IN arguments, this field will be null. Note that subscripting is 1-based, whereas for historical reasons proargtypes is subscripted from 0.
proargmodes char[] An array with the modes of the function arguments, encoded as i for IN arguments, o for OUT arguments, b for INOUT arguments, v for VARIADIC arguments, t for TABLE arguments. If all the arguments are IN arguments, this field will be null. Note that subscripts correspond to positions of proallargtypes not proargtypes .
proargnames text[] An array with the names of the function arguments. Arguments without a name are set to empty strings in the array. If none of the arguments have a name, this field will be null. Note that subscripts correspond to positions of proallargtypes not proargtypes .
proargdefaults pg_node_tree Expression trees (in nodeToString() representation) for default values. This is a list with pronargdefaults elements, corresponding to the last N input arguments (i.e., the last N proargtypes positions). If none of the arguments have defaults, this field will be null.
protrftypes oid[] Data type OIDs for which to apply transforms.
prosrc text This tells the function handler how to invoke the function. It might be the actual source code of the function for interpreted languages, a link symbol, a file name, or just about anything else, depending on the implementation language/call convention.
probin text Additional information about how to invoke the function. Again, the interpretation is language-specific.
proconfig text[] Function's local settings for run-time configuration variables
proacl aclitem[] Access privileges; see GRANT and REVOKE for details

For compiled functions, both built-in and dynamically loaded, prosrc contains the function's C-language name (link symbol). For all other currently-known language types, prosrc contains the function's source text. probin is unused except for dynamically-loaded C functions, for which it gives the name of the shared library file containing the function.