apache/cassandra · error · IllegalArgumentException

Amount of transient nodes should be strictly positive, but…

Error message

Amount of transient nodes should be strictly positive, but was: '%d'

What it means

When parsing a replication factor string with a transient component, the transient RF count must be strictly positive (the '/0' case is rejected) and never negative. ReplicationFactor.validate throws this IllegalArgumentException if the transient portion is negative, indicating malformed replication syntax.

Solutions

Fix the replication string so the transient count is a positive integer, e.g. 'dc1':'5/1'
Validate that transient replicas < full replicas before submitting the schema change
Re-run the CREATE/ALTER KEYSPACE with the corrected value

Example fix

// before
CREATE KEYSPACE ks WITH replication = {'class':'NetworkTopologyStrategy','dc1':'5/-1'};
// after
CREATE KEYSPACE ks WITH replication = {'class':'NetworkTopologyStrategy','dc1':'5/1'};

Defensive patterns

Strategy: validation

Validate before calling

static ReplicationFactor parseRf(String s) {
    String[] parts = s.split("/");
    int full = Integer.parseInt(parts[0]);
    int transientRf = parts.length > 1 ? Integer.parseInt(parts[1]) : 0;
    if (transientRf < 0) throw new IllegalArgumentException("transient RF must be > 0: " + s);
    if (transientRf >= full) throw new IllegalArgumentException("transient RF must be < full RF: " + s);
    return ReplicationFactor.fromString(s);
}

Try / catch

try { session.execute(createKeyspaceCql); }
catch (InvalidQueryException e) { if (e.getMessage().contains("transient")) { /* correct the RF string and retry */ } }

Prevention

Validate RF strings ('n/m' with 0 < m < n) in schema tooling before applying
Use constants/templates instead of interpolating raw numbers into replication maps
Add schema linting in CI for keyspace definitions

When it happens

Trigger: Defining replication with a negative transient count, e.g. 'dc1':'3/-1', or programmatic construction of a ReplicationFactor with transientRF < 0 (note: transientRF == 0 is also rejected when a '/' separator was present).

Common situations: Typo in the RF string in CREATE KEYSPACE; scripted generation of replication options with unvalidated/interpolated numbers; misconfigured tooling emitting 'n/-m'.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/368fcfa3840ec06c. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/locator/ReplicationFactor.java:83

                                    "Transient replication is not enabled on this node");
        Preconditions.checkArgument(totalRF >= 0,
                                    "Replication factor must be non-negative, found %s", totalRF);
        Preconditions.checkArgument(transientRF == 0 || transientRF < totalRF,
                                    "Transient replicas must be zero, or less than total replication factor. For %s/%s", totalRF, transientRF);
        if (transientRF > 0)
        {
            Preconditions.checkArgument(DatabaseDescriptor.getNumTokens() == 1,
                                        "Transient nodes are not allowed with multiple tokens");
            Stream<InetAddressAndPort> endpoints = Stream.concat(Gossiper.instance.getLiveMembers().stream(), Gossiper.instance.getUnreachableMembers().stream());
            List<InetAddressAndPort> badVersionEndpoints = endpoints.filter(Predicates.not(FBUtilities.getBroadcastAddressAndPort()::equals))
                                                                    .filter(endpoint -> Gossiper.instance.getReleaseVersion(endpoint) != null && Gossiper.instance.getReleaseVersion(endpoint).major < 4)
                                                                    .collect(Collectors.toList());
            if (!badVersionEndpoints.isEmpty())
                throw new IllegalArgumentException("Transient replication is not supported in mixed version clusters with nodes < 4.0. Bad nodes: " + badVersionEndpoints);
        }
        else if (transientRF < 0)
        {
            throw new IllegalArgumentException(String.format("Amount of transient nodes should be strictly positive, but was: '%d'", transientRF));
        }
    }

    public boolean equals(Object o)
    {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        ReplicationFactor that = (ReplicationFactor) o;
        return allReplicas == that.allReplicas && fullReplicas == that.fullReplicas;
    }

    public int hashCode()
    {
        return Objects.hash(allReplicas, fullReplicas);
    }

    public static ReplicationFactor fullOnly(int totalReplicas)
    {

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