在mysql数据库池中请求连接时达到的用户限制

Question

In node js,I have created a pool for database connectivity

var pool = mysql.createPool( // use a pool for multiple connections
{
  connectionLimit : 4,
  waitForConnections : true,
  queueLimit : 0,
  host     : hostName,
  user     : userName,
  password : passName,
  database : databaseName
});

After making four connections the code works fine. But after five connection requests are queued in pool for connection and then I make a connection request as

pool.getConnection(funtion(err){
  if(err)
    console.log('[error] with connection'+err);
});

Then Error occurs --->

[error] with connection Error: ER_USER_LIMIT_REACHED: User 'b1312146aa0cc6' has
exceeded the 'max_user_connections' resource (current value: 4)

Answer 1

try this:

var mysql = require('mysql');

var pool = mysql.createPool({
    connectionLimit: 4,
    waitForConnections: true,
    queueLimit: 0,
    host: hostName,
    user: userName,
    password: passName,
    database: databaseName
});

var sql = 'select * from bag where id = ?';
var args = [1]

pool.query(sql, args, function(err, result) {
    console.log('result:', result);
})

pool.query(sql, args, function(err, result) {
    console.log('result:', result);
})

pool.query(sql, args, function(err, result) {
    console.log('result:', result);
})

pool.query(sql, args, function(err, result) {
    console.log('result:', result);
})

pool.query(sql, args, function(err, result) {
    console.log('result:', result);
})

// ...