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给出以下节点\ JavaScript代码,由于某些原因,计数器变量(failedCounter, successMatchedCounter, successUnmatchedCounter
)在运行时以意外方式计算。我认为这是一个范围问题,是异步的问题,但仍然无法找到原因。数字变量递增 - 运行时发生意外的数字
更新:我认为,当以connection.query()
所有呼叫完成我应该得到通知,然后才记录的计数器..
见"//BUG: counted numbers are not logged as expected"
行:
var MongoClient = require('mongodb').MongoClient;
var mysql = require('mysql2');
var fs = require('fs');
var dir = './logs';
if (!fs.existsSync(dir)) {
fs.mkdirSync(dir);
}
var testMode = false;
var mongoUrl = 'mongodb://xxx:27017/yy';
var mySqlconnString = {
host: 'xxxxx',
user: 'xxxx',
password: 'xxxxx',
database: 'xxxxx'
};
var connection = mysql.createConnection(mySqlconnString);
connection.connect(function(err) {
if (err) {
console.log('Error connecting to MySql DB');
return;
}
console.log('Connection established to MySql DB');
MongoClient.connect(mongoUrl, function(err, db) {
if (err) {
console.log('Error connecting to MongoDB');
return;
}
console.log("Connection established to MongoDB");
markSitesAsDeleted(db, function() {
console.log('closing DBs connections..');
connection.end(function(err) {});
db.close();
});
});
});
var failedCounter = 0;
var successMatchedCounter = 0;
var successUnmatchedCounter = 0;
var totalCounter = 0;
var markSitesAsDeleted = function(db, closeConnectionsCallback) {
console.log(`\nMigration process is starting..`);
var cursor = db.collection('someCollection').find({
"isDeleted": true
});
console.log(`Migrating data..\r\n`);
cursor.each(function(err, siteDoc) {
if (siteDoc != null) {
var siteID = Math.trunc(siteDoc._id)
if (testMode === false) {
connection.query(`CALL MarkSiteAsDeleted_3(${siteID})`, function(error, rows) {
if (error) {
//TODO: Print error
failedCounter++;
fs.appendFileSync('logs/log.txt', `Error occured when calling MarkSiteAsDeleted_3 SP for SiteId=${siteID}. see error: ${JSON.stringify(error)}\n`);
} else {
if (rows.affectedRows === 1) { // Has match
successMatchedCounter++;
} else {
successUnmatchedCounter++;
}
}
});
}
totalCounter++;
} else {
//BUG: counted numbers are not logged as expected
fs.appendFileSync('logs/log.txt', `Total: ${totalCounter}, Success and Matched: ${successMatchedCounter}, Success but Unmatched: ${successUnmatchedCounter}, Failed: ${failedCounter}\r\n`);
closeConnectionsCallback();
}
});
};
如何在所有异步查询完成后收到通知? –
没有人回答“在完成所有查询后我如何得到通知?”。有完整的图书馆,网站,论坛和专门讨论这个确切问题的帖子。这是一个设计问题,我不熟悉你的设计以及你在编写代码时如何处理异步任何事情。 – gforce301