Node-mysqlでの接続プールコード学習
8896 ワード
node-mysqlはnodeです.js下のmysql駆動は,この間接続プールの問題を処理する上で接続が解放されない難病に遭遇し,解決したが,次回の重複を避けるための経験をまとめる必要がある.次はnode-mysqlの接続プールのコードの一部で、メモ用に詳細なログを追加しました.
/**
* Connection
* @param cb
* @returns {*}
*/
Pool.prototype.getConnection = function (cb) {
//
console.log("getConnection _allConnections.length: %j, _freeConnections.length: %j", this._allConnections.length, this._freeConnections.length);
//
if (this._closed) {
return process.nextTick(function () {
return cb(new Error('Pool is closed.'));
});
}
var connection;
// Connection， 0
if (this._freeConnections.length > 0) {
connection = this._freeConnections.shift();
return process.nextTick(function () {
return cb(null, connection);
});
}
// （ 10）， （ CreateConnection）
if (this.config.connectionLimit === 0 || this._allConnections.length < this.config.connectionLimit) {
connection = new PoolConnection(this, { config: this.config.connectionConfig });
//
this._allConnections.push(connection);
// Connection
return connection.connect(function (err) {
if (this._closed) {
return cb(new Error('Pool is closed.'));
}
if (err) {
return cb(err);
}
this.emit('connection', connection);
return cb(null, connection);
}.bind(this));
}
// （ True），False
if (!this.config.waitForConnections) {
return process.nextTick(function () {
return cb(new Error('No connections available.'));
});
}
// （ 0， ）
if (this.config.queueLimit && this._connectionQueue.length >= this.config.queueLimit) {
return cb(new Error('Queue limit reached.'));
}
//
this._connectionQueue.push(cb);
};
/**
* Connection
* @param connection
*/
Pool.prototype.releaseConnection = function (connection) {
var cb;
//
if (!connection._pool) {
//
if (this._connectionQueue.length) {
//
cb = this._connectionQueue.shift();
// getConnection Connection
process.nextTick(this.getConnection.bind(this, cb));
}
}
/**
*
*/
else if (this._connectionQueue.length) {
cb = this._connectionQueue.shift();
// connection
process.nextTick(cb.bind(null, null, connection));
}
//
else {
// connection ，
this._freeConnections.push(connection);
//
console.log("releaseConnection _allConnections.length: %j, _freeConnections.length: %j", this._allConnections.length, this._freeConnections.length);
}
};