changeUser return err

[freedaxin]

// ... connect and query
connection.changeUser({}, function (err) {
console.log(err);
});

callback err:

{ [Error: ER_UNKNOWN_COM_ERROR: Unknown command] code: 'ER_UNKNOWN_COM_ERROR', fatal: true }

my mysql version is 5.1.42, which should have support change user command.

[felixge]

Can you post the output when setting debug: true for the connection?

[freedaxin]

var mysql      = require('/data0/npm/node_modules/mysql');

var connection = mysql.createConnection({
  host     : '10.75.19.79',
  port     : 9601,
  user     : 'maya',
  password : 'maya123456',
  database : 'test',
  debug    : true,
});

connection.connect();

connection.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
  if (err) throw err;

  console.log('The solution is: ', rows[0].solution);
});

//connection.changeUser({}, function (err) {
  console.log('err:', err);
});

connection.end();

output:

<-- HandshakeInitializationPacket
{ protocolVersion: 10,
  serverVersion: '5.1.42-log',
  threadId: 10148466,
  scrambleBuff1: <Buffer 64 3e 48 2f 50 27 6e 75>,
  filler1: <Buffer 00>,
  serverCapabilities1: 63487,
  serverLanguage: 33,
  serverStatus: 2,
  serverCapabilities2: 0,
  scrambleLength: 0,
  filler2: <Buffer 00 00 00 00 00 00 00 00 00 00>,
  scrambleBuff2: <Buffer 26 57 63 6d 7b 42 76 4b 52 3b 6e 39>,
  filler3: <Buffer 00>,
  pluginData: undefined,
  protocol41: true }

--> ClientAuthenticationPacket
{ clientFlags: 193487,
  maxPacketSize: 0,
  charsetNumber: 33,
  filler: undefined,
  user: 'maya',
  scrambleBuff: <Buffer 23 83 02 c5 b3 1a 90 a2 d2 7f 99 ec db 41 03 55 da 86 c8 29>,
  database: 'test',
  protocol41: true }

<-- OkPacket
{ fieldCount: 0,
  affectedRows: 0,
  insertId: 0,
  serverStatus: 2,
  warningCount: 0,
  message: '',
  protocol41: true,
  changedRows: 0 }

--> ComQueryPacket
{ command: 3, sql: 'SELECT 1 + 1 AS solution' }

<-- ResultSetHeaderPacket
{ fieldCount: 1, extra: undefined }

<-- FieldPacket
{ catalog: 'def',
  db: '',
  table: '',
  orgTable: '',
  name: 'solution',
  orgName: '',
  filler1: <Buffer 0c>,
  charsetNr: 63,
  length: undefined,
  type: 8,
  flags: 129,
  decimals: 0,
  filler2: <Buffer 00 00>,
  default: undefined,
  zeroFill: false,
  protocol41: true,
  fieldLength: 3 }

<-- EofPacket
{ fieldCount: 254,
  warningCount: 0,
  serverStatus: 2,
  protocol41: true }

<-- RowDataPacket
{ solution: 2 }

<-- EofPacket
{ fieldCount: 254,
  warningCount: 0,
  serverStatus: 2,
  protocol41: true }

The solution is:  2
--> ComChangeUserPacket
{ command: 17,
  user: 'maya',
  scrambleBuff: <Buffer 23 83 02 c5 b3 1a 90 a2 d2 7f 99 ec db 41 03 55 da 86 c8 29>,
  database: 'test',
  charsetNumber: 33 }

<-- ErrorPacket
{ fieldCount: 255,
  errno: 1047,
  sqlStateMarker: '#',
  sqlState: '08S01',
  message: 'Unknown command' }

err: { [Error: ER_UNKNOWN_COM_ERROR: Unknown command] code: 'ER_UNKNOWN_COM_ERROR', fatal: true }

[dougwilson]

Are you able to use any of the GRANT commands on that server? Typically I have seen the change user command return Unknown command if the server is started with --skip-grant-tables.

[freedaxin]

to dougwilson:
I can use grant on the connection, but still error.

[freedaxin]

I've run the same test with php mysqli_change_user(), and it works, so there's no problem with mysql.

[freedaxin]

I read the mysql protocol:
http://dev.mysql.com/doc/internals/en/text-protocol.html#packet-COM_CHANGE_USER

and found that character-set should be 2 bytes, but in ComChangeUserPacket.js it's 1 byte.
I changed it to 2:

    writer.writeUnsignedNumber(2, this.charsetNumber);

And run the test again, it seems ok now:

{ command: 17,
  user: 'root',
  scrambleBuff: <Buffer 4e 62 44 33 f7 8f 73 2c 2b 70 1d b5 7a 73 9a 61 d8 cb f8 01>,
  database: 'test',
  charsetNumber: 33 }

<-- OkPacket
{ fieldCount: 0,
  affectedRows: 0,
  insertId: 0,
  serverStatus: 2,
  warningCount: 0,
  message: '',
  protocol41: true,
  changedRows: 0 }

Can you confirm and fix it?
Thanks very much!

[felixge]

@freedaxin I think you're right. If you send a patch, I'd be happy to merge it.

[felixge]

Should be fixed by #498 now.

[freedaxin]

ok