Question

I use node.js and mysql module to write a simple select statement.

The problem is it can only respond to one request, subsequent responses will be empty.

I use a browser to load the page for the first time, it return a complete result, but the browser is still loading. What happen:

Code:

var server = http.createServer(function (request, response) {
      response.writeHead(200, {"Content-Type": "text/plain"});

      client.query('SELECT * FROM ' + tbl,
          function selectDb(err, results, fields) {
            if (err) {
              throw err;
            }

            for (var i in results){
              var result = results[i];
              response.write(result['CUSTOMERNAME']); // Writes to the web browser the value of test then a : to seperate values
            }

            response.end("END RESULT");

            client.end();
          }
      );

});

Answer 1

According to the node-mysql docs (which I assume you are using) found here,

client.end();

Closes the mysql connection.

When you attempt another request, there is no open connection and node-mysql doesn’t do any connection pool handling or auto re-connect, its all left up to you.

If you don’t mind keeping a single connection open for the lifetime of the app (not the best design) you can just move that client.end() outside your connection handler.

Otherwise, create a little method that checks for an open connection or maybe does a connection pool, see this post for more info.