nodejs mysql Error Connection lost The server closed the connection

Question

when I use node mysql  an error is appear between 12 00 to 2 00 that the TCP connection is shutdown by the server  This is the full message   Error  Connection lost  The server closed the connection  at Protocol end   opt node-v0 10 20-linux-x64 IM node modules mysql lib protocol Protocol js 73 13  at Socket onend  stream js 79 10  at Socket EventEmitter emit  events js 117 20  at  stream readable js 920 16 at process  tickCallback  node js 415 13    There is the solution  However  after I try by this way  the problem also appear  now I do not know how to do  Does anyone meet this problem   Here is the way I wrote follow the solution       var handleKFDisconnect   function         kfdb on  error   function err            if   err fatal                return                    if  err code      PROTOCOL CONNECTION LOST                 console log  PROTOCOL CONNECTION LOST                throw err                    log error  The database is error     err stack            kfdb   mysql createConnection kf config            console log  kfid             console log kfdb           handleKFDisconnect                     handleKFDisconnect

User · Answer

To simulate a dropped connection try  connection destroy      More information here  https   github com felixge node-mysql blob master Readme md terminating-connections

User · Answer

better solution is to use pool - ill handle this for you    x000D   x000D  const pool   mysql createPool   x000D    host   localhost   x000D    user   --   x000D    database   ---   x000D    password   ----  x000D      x000D   x000D         later x000D  pool query  select 1   1    err  rows    gt              x000D   x000D   x000D    https   github com sidorares node-mysql2 issues 836

User · Answer

Try to use this code to handle server disconnect   var db config       host   localhost       user   root       password          database   example      var connection   function handleDisconnect       connection   mysql createConnection db config      Recreate the connection  since                                                      the old one cannot be reused     connection connect function err                    The server is either down     if err                                           or restarting  takes a while sometimes         console log  error when connecting to db    err         setTimeout handleDisconnect  2000      We introduce a delay before attempting to reconnect                                               to avoid a hot loop  and to allow our node script to                                              process asynchronous requests in the meantime                                               If you re also serving http  display a 503 error    connection on  error   function err        console log  db error   err       if err code      PROTOCOL CONNECTION LOST        Connection to the MySQL server is usually       handleDisconnect                               lost due to either server restart  or a       else                                           connnection idle timeout  the wait timeout       throw err                                      server variable configures this                 handleDisconnect      In your code i am missing the parts after connection   mysql createConnection db config

User · Answer

Creating and destroying the connections in each query maybe complicated  i had some headaches with a server migration when i decided to install MariaDB instead MySQL  For some reason in the file etc my cnf the parameter wait timeout had a default value of 10 sec  it causes that the persistence can t be implemented   Then  the solution was set it in 28800  that s 8 hours  Well  i hope help somebody with this  g  evonada     excuse me for my bad english

User · Answer

I do not recall my original use case for this mechanism  Nowadays  I cannot think of any valid use case   Your client should be able to detect when the connection is lost and allow you to re-create the connection  If it important that part of program logic is executed using the same connection  then use transactions   tl dr  Do not use this method     A pragmatic solution is to force MySQL to keep the connection alive   setInterval function          db query  SELECT 1       5000     I prefer this solution to connection pool and handling disconnect because it does not require to structure your code in a way thats aware of connection presence  Making a query every 5 seconds ensures that the connection will remain alive and PROTOCOL CONNECTION LOST does not occur   Furthermore  this method ensures that you are keeping the same connection alive  as opposed to re-connecting  This is important  Consider what would happen if your script relied on LAST INSERT ID   and mysql connection have been reset without you being aware about it   However  this only ensures that connection time out  wait timeout and interactive timeout  does not occur  It will fail  as expected  in all others scenarios  Therefore  make sure to handle other errors

[mysql] nodejs mysql Error: Connection lost The server closed the connection

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