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[英]UnhandledPromiseRejectionWarning even though wrapped in try/catch()
[英]"UnhandledPromiseRejectionWarning" in nodejs even after adding catch block
我正在為 postgres 數據庫編寫 api 服務器,並且正在測試一些壓力情況。 我正在使用模塊 node-postgres 中的一個池,並遇到了這個問題。
在啟動服務器之前,我首先用盡了所有的 postgers 連接。 然后我嘗試通過池運行查詢。
我嘗試在承諾周圍添加 try catch 塊。 在承諾內(在 catch 塊內),沒有任何幫助。
以下是我重現錯誤的一些測試代碼。
var pg = require('./node_modules/pg')
var pool = new pg.Pool(
{
user: "test",
password: "pass134",
host: "localhost",
database: "testdb",
port: 5432,
max: 32,
min: 16,
idleTimeoutMillis: 60000,
connectionTimeoutMillis: 10000
}
);
pool.on("error", function(err){
console.log("Error1: " + String(err));
});
pool.query("SELECT COUNT(*) FROM acal_cust", [])
.then(function(err, results){
console.log(err);
console.log(results);
}).catch(function(err){
console.log("Error2:" + String(err));
pool.end();
});
這是我運行代碼時得到的。
Error2: error: sorry, too many clients already
(node:10422) UnhandledPromiseRejectionWarning: error: sorry, too many clients already
at Connection.parseE (/ext/node_modules/pg/lib/connection.js:554:11)
at Connection.parseMessage (/ext/node_modules/pg/lib/connection.js:381:17)
at Socket.<anonymous> (/ext/node_modules/pg/lib/connection.js:117:22)
at emitOne (events.js:116:13)
at Socket.emit (events.js:211:7)
at addChunk (_stream_readable.js:263:12)
at readableAddChunk (_stream_readable.js:250:11)
at Socket.Readable.push (_stream_readable.js:208:10)
at TCP.onread (net.js:597:20)
(node:10422) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:10422) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
我想知道如何正確處理錯誤。 這樣它就不會被拋出。
捕獲未處理的拒絕
process.on('unhandledRejection', error => { // Will print "unhandledRejection err is not defined" console.log('unhandledRejection', error.message); });
catch 塊是用於承諾而不是用於異步代碼的回調版本。 因此,如果將拋出任何錯誤,它將被捕獲在 if(err) {//do nothing} 或
pool.query("SELECT COUNT(*) FROM acal_cust", []).then((results) => { console.log(results); }).catch(function(err){ console.log("Error:" + String(err)); });
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