PostgreSQL throws undefined_function (error code 42883) when it cannot find a function that matches the supplied name and argument types.
PostgreSQL undefined_function (error 42883) occurs when the database cannot find a function with the given name and argument types. Check spelling, schema search_path, argument types, and installed extensions. Creating or casting to the correct function resolves the issue.
PostgreSQL Error 42883
The undefined_function error means PostgreSQL could not locate a function whose name and input types match the call you issued. It raises SQLSTATE 42883 and aborts the statement.
The error appears during SELECT, INSERT, UPDATE, or any call that invokes a function or operator that PostgreSQL ultimately rewrites to a function.
Calling a function that was never created is the most common trigger.
A typo in the function name or missing schema qualification prevents PostgreSQL from resolving it.
Mismatched argument data types also cause 42883. PostgreSQL considers the combination of name and argument types when looking up a function, so varchar versus text can break resolution.
First, verify the function exists with \df in psql or querying pg_proc.
If missing, create it or install the needed extension.
Second, ensure your search_path includes the schema where the function lives or reference it explicitly (schema.func_name).
Scenario: using lower() on a citext column returns 42883 because lower(citext) is undefined. Solution: CAST to text or install the citext extension which adds compatible functions.
Scenario: calling public.my_sum(integer, integer) while only public.my_sum(numeric, numeric) exists.
Solution: cast arguments or create an integer overload.
Prefix function calls with schema names in production code to avoid search_path surprises. Maintain controlled extension lists across environments so each database has identical function catalogs.
Write automated tests that execute critical functions after migrations. Immediate feedback prevents 42883 from reaching production.
Error 42704 undefined object occurs when a relation or type is missing.
Fix it by creating or referencing the correct object.
Error 42804 wrong_object_type surfaces when a function returns an unexpected type. Adjust return type or calling context.
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The function may live in a different schema than your current search_path. Qualify the call with schema.function or adjust search_path.
Yes. Operators are implemented as functions. If PostgreSQL cannot find a matching operator signature, it raises 42883.
Run \df+ function_name in psql to inspect existing signatures and compare them to the types you pass.
Galaxy autocompletes only existing functions in the connected database and highlights unresolved calls, reducing the chance of 42883 in saved queries.
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