apache/cassandra · error · IOException

Corrupted input: expected byte 1, 2, 3, 4 or 5; received

Error message

Corrupted input: expected byte 1, 2, 3, 4 or 5; received 

What it means

deserializeSubset decodes an Unseekables that is a subset of a known superset, using the same 1-6 kind byte scheme. An unrecognized byte throws IOException, meaning the payload is not a valid serialized Unseekables subset — corruption, misalignment, or encoder/decoder version mismatch.

Source

Thrown at src/java/org/apache/cassandra/service/accord/serializers/KeySerializers.java:385

                case 1: kind = UnseekablesKind.RoutingKeys; result = (RS)routingKeys.deserialize(in); break;
                case 2: kind = UnseekablesKind.PartialKeyRoute; result = (RS)partialKeyRoute.deserialize(in); break;
                case 3: kind = UnseekablesKind.FullKeyRoute; result = (RS)fullKeyRoute.deserialize(in); break;
                case 4: kind = UnseekablesKind.RoutingRanges; result = (RS)ranges.deserialize(in); break;
                case 5: kind = UnseekablesKind.PartialRangeRoute; result = (RS)partialRangeRoute.deserialize(in); break;
                case 6: kind = UnseekablesKind.FullRangeRoute; result = (RS)fullRangeRoute.deserialize(in); break;
            }
            Invariants.require(permitted.contains(kind));
            return result;
        }

        public RS deserializeSubset(Unseekables<?> superset, DataInputPlus in) throws IOException
        {
            byte b = in.readByte();
            UnseekablesKind kind;
            RS result;
            switch (b)
            {
                default: throw new IOException("Corrupted input: expected byte 1, 2, 3, 4 or 5; received " + b);
                case 1: kind = UnseekablesKind.RoutingKeys; result = (RS)routingKeys.deserializeSubset((AbstractUnseekableKeys) superset, in); break;
                case 2: kind = UnseekablesKind.PartialKeyRoute; result = (RS)partialKeyRoute.deserializeSubset((AbstractUnseekableKeys) superset, in); break;
                case 3: kind = UnseekablesKind.FullKeyRoute; result = (RS)fullKeyRoute.deserializeSubset((AbstractUnseekableKeys) superset, in); break;
                case 4: kind = UnseekablesKind.RoutingRanges; result = (RS)ranges.deserializeSubset((AbstractRanges) superset, in); break;
                case 5: kind = UnseekablesKind.PartialRangeRoute; result = (RS)partialRangeRoute.deserializeSubset((AbstractRanges) superset, in); break;
                case 6: kind = UnseekablesKind.FullRangeRoute; result = (RS)fullRangeRoute.deserializeSubset((AbstractRanges) superset, in); break;
            }
            Invariants.require(permitted.contains(kind));
            return result;
        }

        public void skip(DataInputPlus in) throws IOException
        {
            countAndSkip(in);
        }

        public void skip(UnseekablesKind kind, DataInputPlus in) throws IOException
        {

View on GitHub (pinned to 88fd0f6a0e)

Solutions

1. Ensure all nodes use compatible Accord serializer versions (complete rolling upgrade).
2. Inspect the received byte against UnseekablesKind values to find the encoding mismatch.
3. Check the connection for earlier deserialization errors that misaligned the stream and reset it if found.
4. Update the switch when new UnseekablesKind values are introduced.

try {
    Unseekables<?, ?> subset = serializer.deserializeSubset(superset, in);
} catch (IOException e) {
    if (e.getMessage().startsWith("Corrupted input")) {
        logger.warn("Corrupt Unseekables subset payload; dropping message", e);
    } else throw e;
}

When it happens

Trigger: deserializeSubset(superset, in) reads a kind byte outside 1..6 when decoding a subset of Unseekables/Route relative to a superset.

Common situations: Rolling-upgrade version skew; corrupted or truncated network data; a preceding read failure leaving the stream mid-record; tests passing fabricated bytes.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Corrupted input: expected byte 1, 2, 3, 4, 5 or 6; received
• Unhandled CheckStatusReply kind:
• Corrupted input: expected byte 1 or 2, received " + b
• Invalid 64-bits double value, expecting 8 bytes but got
• Invalid 32-bits float value, expecting 4 bytes but got

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/bec2f9549a66157e. Report an issue: GitHub.