apache/cassandra · error · InvalidRequestException

Unknown function %s called

Error message

Unknown function %s called

What it means

FunctionCall.Raw.prepare() resolves the function name via FunctionResolver against the provided argument terms and current user functions. If the resolver returns null (no signature matches the name/args in that keyspace), the statement cannot be prepared and this InvalidRequestException is thrown.

Source

Thrown at src/java/org/apache/cassandra/cql3/functions/FunctionCall.java:162

        }

        public static Raw newNegation(Term.Raw raw)
        {
            FunctionName name = FunctionName.nativeFunction(OperationFcts.NEGATION_FUNCTION_NAME);
            return new Raw(name, Collections.singletonList(raw));
        }

        public static Raw newCast(Term.Raw raw, CQL3Type type)
        {
            FunctionName name = FunctionName.nativeFunction(CastFcts.getFunctionName(type));
            return new Raw(name, Collections.singletonList(raw));
        }

        public Term prepare(String keyspace, ColumnSpecification receiver) throws InvalidRequestException
        {
            Function fun = FunctionResolver.get(keyspace, name, terms, receiver.ksName, receiver.cfName, receiver.type, UserFunctions.getCurrentUserFunctions(name, keyspace));
            if (fun == null)
                throw invalidRequest("Unknown function %s called", name);
            if (fun.isAggregate())
                throw invalidRequest("Aggregation function are not supported in the where clause");

            ScalarFunction scalarFun = (ScalarFunction) fun;

            // Functions.get() will complain if no function "name" type check with the provided arguments.
            // We still have to validate that the return type matches however
            if (!scalarFun.testAssignment(keyspace, receiver).isAssignable())
            {
                if (OperationFcts.isOperation(name))
                    throw invalidRequest("Type error: cannot assign result of operation %s (type %s) to %s (type %s)",
                                         OperationFcts.getOperator(scalarFun.name()), scalarFun.returnType().asCQL3Type(),
                                         receiver.name, receiver.type.asCQL3Type());

                throw invalidRequest("Type error: cannot assign result of function %s (type %s) to %s (type %s)",
                                     scalarFun.name(), scalarFun.returnType().asCQL3Type(),
                                     receiver.name, receiver.type.asCQL3Type());
            }

View on GitHub (pinned to 88fd0f6a0e)

Solutions

  1. Verify the function exists: SELECT * FROM system_schema.functions WHERE function_name = 'myfunc';
  2. Qualify the function with its keyspace: schema.myFunc(x)
  3. CREATE the function in the keyspace the query targets
  4. Fix typos and check the exact argument count/types match an existing overload

Example fix

// before
SELECT myFunc(x) FROM t;
// after
SELECT ks.myFunc(x) FROM t; -- or create it first:
CREATE FUNCTION ks.myFunc(x int) RETURNS NULL ON NULL INPUT RETURNS int LANGUAGE java AS 'return x;';
Defensive patterns

Strategy: validation

Validate before calling

const known = (await session.execute("SELECT function_name FROM system_schema.functions WHERE keyspace_name = 'ks'")).rows.map(r => r.function_name);
if (!known.includes('myfunc')) throw new Error('function myfunc does not exist in ks');

Try / catch

try { rs = session.execute(q); } catch (InvalidRequestException e) { if (e.getMessage().startsWith('Unknown function')) { /* create/qualify function */ } else throw e; }

Prevention

When it happens

Trigger: A function name in a SELECT/WHERE term that does not exist (or exists with an incompatible signature) in the target keyspace, e.g. `SELECT myFunc(x) FROM t` where myFunc was never CREATEd in that keyspace.

Common situations: Calling a user-defined function created in a different keyspace without qualifying it; typos in native function names; using an aggregate function name in a non-aggregate position; running against a cluster where the function was never deployed.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/74feb2f8ed9dca84. Report an issue: GitHub.