apache/cassandra · error · InvalidRequestException

Invalid operation (%s) for non list column %s

Error message

Invalid operation (%s) for non list column %s

What it means

InvalidRequestException from Operation.Prepend.prepare: a prepend ('+ value on the left') update operation was applied to a column whose type is not a list. Only list columns support prepend semantics; the receiver's type is checked against ListType after preparing the value term.

Source

Thrown at src/java/org/apache/cassandra/cql3/Operation.java:466

            return !(other instanceof SetValue);
        }
    }

    public static class Prepend implements RawUpdate
    {
        private final Term.Raw value;

        public Prepend(Term.Raw value)
        {
            this.value = value;
        }

        public Operation prepare(TableMetadata metadata, ColumnMetadata receiver, boolean canReadExistingState) throws InvalidRequestException
        {
            Term v = value.prepare(metadata.keyspace, receiver);

            if (!(receiver.type instanceof ListType))
                throw new InvalidRequestException(String.format("Invalid operation (%s) for non list column %s", toString(receiver), receiver.name));
            else if (!(receiver.type.isMultiCell()))
                throw new InvalidRequestException(String.format("Invalid operation (%s) for frozen list column %s", toString(receiver), receiver.name));

            return new Lists.Prepender(receiver, v);
        }

        protected String toString(ColumnSpecification column)
        {
            return String.format("%s = %s - %s", column.name, value, column.name);
        }

        public boolean isCompatibleWith(RawUpdate other)
        {
            return !(other instanceof SetValue);
        }
    }

    public static class ColumnDeletion implements RawDeletion

View on GitHub (pinned to 88fd0f6a0e)

Solutions

1. Target a list column with the prepend syntax
2. For sets, use set addition: s = {x} + s
3. For maps use map addition syntax
4. Correct the literal to match the column's collection kind

Example fix

// before (s is set<text>)
UPDATE t SET s = ['a'] + s WHERE k=1;
// after
UPDATE t SET s = {'a'} + s WHERE k=1;

String type = session.execute("SELECT type FROM system_schema.columns WHERE keyspace_name=? AND table_name=? AND column_name=?", ks, table, col).one().getString("type");
if (!type.startsWith("list")) throw new IllegalStateException("prepend requires a list column, got " + type);

try { session.execute(update); } catch (InvalidQueryException e) { if (e.getMessage().contains("non list column")) { /* use collection-kind-appropriate syntax */ } else throw e; }

When it happens

Trigger: `UPDATE t SET s = [1] + s` where s is a set, map, or scalar column — prepend syntax only works on lists.

Common situations: Mixing up set/list syntax in queries; schema changed from list to set after the query was written; copy-paste between columns of different collection kinds.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Value for a map addition has to be a map, but was: '%s'
• Value for a map substraction has to be a set, but was: '%s'
• Unexpected receiver type '%s'; only list and vector are expe
• Invalid list literal for %s of type %s
• Invalid list literal for %s: value %s is not of type %s

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/dbfccf343aeaeaed. Report an issue: GitHub.