apache/cassandra · error · InvalidRequestException

Unkown field in user type

Error message

Unkown field %s in user type %s

What it means

During ALTER TYPE ... RENAME, each requested old field name is looked up in the UDT; if it is not found and IF EXISTS was not given for the field, the rename fails with an InvalidRequest. Note the message contains a typo ('Unkown') and omits the keyspace argument in the format call relative to its message text — the real message will show only the field and type name plus an extra argument artifact.

Solutions

1. Check the current fields with `DESCRIBE TYPE myks.addr` (or system_schema.types) and correct the old field name in the ALTER statement
2. Use the IF EXISTS clause (`ALTER TYPE ... RENAME city TO town IF EXISTS`) to make a missing field a no-op
3. Fix case sensitivity by quoting the identifier exactly as it was defined, e.g. RENAME "City" TO "Town"

Example fix

// before
ALTER TYPE myks.addr RENAME city TO town; -- Unknown field city
// after
ALTER TYPE myks.addr RENAME town_old TO town; -- use actual field name, or:
ALTER TYPE myks.addr RENAME city TO town IF EXISTS;

// Verify the field exists before renaming:
Row typeRow = session.execute("SELECT field_names FROM system_schema.types WHERE keyspace_name='myks' AND type_name='addr'").one();
List<String> fields = typeRow.getList("field_names", String.class);
if (!fields.contains("city")) throw new IllegalArgumentException("field 'city' does not exist on addr");

try { session.execute(renameCql); }
catch (InvalidQueryException e) {
    if (e.getMessage().contains("Unkown field")) { /* inspect DESCRIBE TYPE / system_schema.types and fix the name */ }
    else throw e;
}

When it happens

Trigger: `ALTER TYPE myks.addr RENAME city TO town` where no field named `city` exists; misspelled field name; running against a keyspace/environment where the type has a different field set; case mismatch (CQL identifiers are case-sensitive in UDTs unless quoted).

Common situations: Typos in field names; quoting/case mistakes (city vs "City"); drift between environments (test vs prod schema); stale migration scripts after an earlier rename.

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

• Duplicate field name
• Altering field types is no longer supported
• Cannot add new field
• Cannot add new field
• Cannot alter user type

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/a7bbc398cee95ecd. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/cql3/statements/schema/AlterTypeStatement.java:228

                        .map(uda -> uda.name().toString())
                        .collect(toList());

            if (!dependentAggregates.isEmpty())
            {
                throw ire("Cannot alter user type %s as it is still used in INITCOND by aggregates %s",
                          userType.getCqlTypeName(),
                          join(", ", dependentAggregates));
            }

            List<FieldIdentifier> fieldNames = new ArrayList<>(userType.fieldNames());

            renamedFields.forEach((oldName, newName) ->
            {
                int idx = userType.fieldPosition(oldName);
                if (idx < 0)
                {
                    if (!ifFieldExists)
                        throw ire("Unkown field %s in user type %s", oldName, userType.getCqlTypeName());
                    return;
                }
                fieldNames.set(idx, newName);
            });

            fieldNames.forEach(name ->
            {
                if (fieldNames.stream().filter(isEqual(name)).count() > 1)
                    throw ire("Duplicate field name %s in type %s", name, keyspaceName, userType.getCqlTypeName());
            });

            return new UserType(keyspaceName, userType.name, fieldNames, userType.fieldTypes(), true);
        }
    }

    private static final class AlterField extends AlterTypeStatement
    {
        private AlterField(String keyspaceName, String typeName, boolean ifExists)

View on GitHub (pinned to 88fd0f6a0e)