" PROTOCOL_ENQUEUE_AFTER_FATAL_ERROR"在Node-MySqL中 [英] "PROTOCOL_ENQUEUE_AFTER_FATAL_ERROR" in Node-MySqL

问题描述

我正在尝试编写Node + Express以提供REST服务.当应用程序启动时，一切都会顺利进行.但是，几个小时后，我收到一个错误:代码":"PROTOCOL_ENQUEUE_AFTER_FATAL_ERROR"，致命":false.似乎有些资源用完了.有人知道如何解决它.

Hi I am trying to write an Node + Express to provide REST services. Everything goes well when the application starts. However, after several hours, I got an error: "code":"PROTOCOL_ENQUEUE_AFTER_FATAL_ERROR","fatal":false. It seems some resources are running out. Did someone know how to fix it.

这是代码的主要部分:

var mysql   = require("mysql");
var _ = require('underscore')
var Q = require("q");

function REST_ROUTER(router,connection,md5) {
    var self = this;
    self.handleRoutes(router,connection,md5);
}

var queryWithPromise = function (connection, query) {
    var deferred = Q.defer();
    connection.query(query, function(err, rows, fields) {
        if (err) {
            deferred.reject(err);
        };
        if (!rows||(rows.length === 0)) {
          deferred.reject("No record!");  
        }
        deferred.resolve(rows);
    });
    return deferred.promise;    
};


REST_ROUTER.prototype.handleRoutes = function(router,connection,md5) {
    var self = this;
    router.get("/",function(req,res){
        res.json({"Message" : "Hello World !"});
    });
    router.get("/data/:token/:latlng",function(req,res){
        //console.log(req.params.token);
        query = mysql.format("SELECT * FROM TOKEN WHERE token=?",[req.params.token]);
        queryWithPromise(connection, query).then(function (tokens) {
            var latlngs = req.params.latlng.split(',');
            var lat = parseFloat(latlngs[0]);
            var lng = parseFloat(latlngs[1]);
            var queryLatLng = mysql.format("SELECT * FROM device WHERE longitude > ? AND longitude < ? AND latitude > ? AND latitude < ?", [lng-0.1, lng+0.1, lat-0.1, lat+0.1]);
            return queryWithPromise(connection, queryLatLng);
        }).then(function (devices) {
            var latlngs = req.params.latlng.split(',');
            var computeDistance = function (fromLatlng, toLatlng) {
                var toRad = function (degree) {
                    return degree * Math.PI / 180;
                };                
                var EARTH_RADIUS = 6378137; // in meter
                var lat1 = toRad(fromLatlng.lat);
                var lng1 = toRad(fromLatlng.lng);
                var lat2 = toRad(toLatlng.lat);
                var lng2 = toRad(toLatlng.lng);
                var d = EARTH_RADIUS*Math.acos(Math.sin(lat1)*Math.sin(lat2) + Math.cos(lat1)*Math.cos(lat2)*Math.cos(lng1 - lng2));
                return d;
            };
            var closestDevice = _.min(devices, function(device) {
                return computeDistance({lat: parseFloat(latlngs[0]), lng: parseFloat(latlngs[1])}, {lat: device.latitude, lng: device.longitude});
            });
            var queryDevice = mysql.format("SELECT * FROM ?? ORDER BY UploadTime DESC LIMIT 100", [closestDevice.device_id]);
            return queryWithPromise(connection, queryDevice);
        }).then(function (data) {
            var latlngs = req.params.latlng.split(',');            
            res.json({
                "latitude": parseFloat(latlngs[0]),
                "longitude": parseFloat(latlngs[1]),
                "timezone": "Asia/Shanghai",
                "offset": 8,
                 "hourly": {
                    "data": _.map(data, function(item) {
                        return {
                            "time": item.UploadTime.getTime()/1000, 
                            "precipIntensity": item.rainfall,
                            "temperature": item.airtemp,
                            "humidity": item.airhumidity,
                            "windSpeed": item.windspeed,
                            "windBearing": item.winddirection,
                            "pressure": item.atmosphericpressure,
                            "soiltemp": item.soiltemp,
                            "soilhumidity": item.soilhumidity
                        };
                    })
                 }
            });
        }).catch(function (error) {
            res.json({"Error" : true, "Message" : "Success", "Data" : error});
        })
        .done();
    });
}

module.exports = REST_ROUTER;

推荐答案

根据我的经验，该问题是由于直接创建连接(使用 mysqljs/mysql 库，不添加createConnection())而不是使用允许运行query()并在执行后自动释放连接的createPool() (执行 + query() + release()).

In my experience that problem was due to creating a connection directly (with mysqljs/mysql library, unsing createConnection()) instead of using createPool() that allows to run query() and releases the connection automatically after execution (doing getConnection() + query() + release()).

在没有释放连接的情况下，在下一次尝试查询时，会发生致命错误.

Without that the connection is not released and, at the next attempt to query, there happens the fatal error.

请参见池连接.

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