Lesson Learned #275: Timeout: Request failed to complete in Node.Js

[Jose_Manuel_Jurado]

Today, a customer reported the following error message using Node.Js and Tedious : Timeout: Request failed to complete in 15000ms
at Connection.requestTimeout (C:\...\NodeJs\node_modules\tedious\lib\connection.js:1257:21)
at Timeout._onTimeout (C:\...\NodeJs\node_modules\tedious\lib\connection.js:1209:14)
at listOnTimeout (node:internal/timers:557:17)
at processTimers (node:internal/timers:500:7) {
code: 'ETIMEOUT', number: undefined, state: undefined, class: undefined, serverName: undefined, procName: undefined, lineNumber: undefined }

Following, I would like to share my findings here:

• This error reported  "Timeout: Request failed to complete in 15000ms" means that the request (TSQL execution) reached the command timeout executing it, for example, using the following code. 

var Connection = require('tedious').Connection;
var Request = require('tedious').Request;
const readline = require('readline');
const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});

var config = {
    server: "servername.database.windows.net", // or "localhost"
    database: "databasename",
    "options": {
        "encrypt": true,
        "requestTimeout": 1000
    },
    authentication: {
        type: "azure-active-directory-password",
        options: {
            userName: "username@domain.com",
            password: "password",
            domain: "7acc0f8a-xxxxx",
        }
    }
};

console.log('Hello world');
var connection = new Connection(config);

// Setup event handler when the connection is established. 
connection.on('connect', function (err) {
    if (err) {
        console.log('Error: ', err)
    }
    // If no error, then good to go...
    console.log('Hello world 2');
    executeStatementWaitFor();
});

connection.connect();

function executeStatementWaitFor() {
    request = new Request("Waitfor Delay '00:01:00'", function (err, rowCount) {
        if (err) {
            console.log(err);
        } else {
            console.log(rowCount + ' rows');
        }
    });

    request.on('row', function (columns) {
        columns.forEach(function (column) {
            console.log(column.value);
        });
    });

    connection.execSql(request);
}

In this situation, increasing the parameter requestTimeout to a higher value and review the basic topics about performance (missing indexes, update statistics and review the execution plan) we could resolve this issue. 

    "options": {
        "encrypt": true,
        "requestTimeout": 1000
    },

Also, if you don't have any log about the TSQL and time spent, using SQL Auditing we could see this query and fix the issue. 

Enjoy!