[v0.25.3] Failed to deserialize data of EventHeaderV4. Possible fixes included.

[qidian99]

I went over the history issues and discovered some similiar issues. I am using v0.25.3, and the error message was:

Caused by: com.github.shyiko.mysql.binlog.event.deserialization.EventDataDeserializationException: Failed to deserialize data of EventHeaderV4{timestamp=1699588796000, eventType=TABLE_MAP, serverId=1, headerLength=19, dataLength=196, nextPosition=16345945, flags=0}

Unsupported table metadata field type 0.

I debugged the program and grabbed all the bytes of event header:

# remaining bytes:
[1, 5, -74, -39, -101, 97, 0, 3, 32, 33, 33, 63, 33, 63, 63, 63, 63, -4, -1, 0, -4, -1, 0, -4, -1, 0, -4, -1, 0, -4, -1, 0, -4, -1, 0, -4, -1, 0, -4, -1, 0]

nColumns = 59 nNumericColumns = 32

It first read the byte 1 for signedness type, which is 1, and after that the length of signedness bytes, which is 5.

// SIGNEDNESS 1, 5, // should read 5 bytes -74, -39, -101, 97, 0,

However, the readBooleanList method actually read 4 bytes instead of 5, missing the 0 as in [...74, -39, -101, 97, 0...], causing the exception when the program tries to read the next type.

private static BitSet readBooleanList(ByteArrayInputStream inputStream, int length) throws IOException {
    BitSet result = new BitSet();
    byte[] bytes = inputStream.read(length + 7 >> 3);

    for(int i = 0; i < length; ++i) {
        if ((bytes[i >> 3] & 1 << 7 - i % 8) != 0) {
            result.set(i);
        }
    }

    return result;
}
actually read: 32+7>>3=4 bytes. missed the 0 byte

Possible fixes

Single line fix:

 case SIGNEDNESS:
     result.setSignedness(readBooleanList(inputStream, nNumericColumns));

to

 case SIGNEDNESS:
     result.setSignedness(readBooleanList(inputStream, fieldLength));

or simply call skipToEndOfTheBlock after reading each metadata