Access Postgres database with AWS Lambda function using Node.js - node.js

Question

My 'handler.js' functions connects to the Postgres database and performs few queries using node.js. My function worked successfully in local, but when accessed as AWS lambda, the queries don't work.
I have also added the corresponding vpc security groups and subnet ids in 'serverless.yml'.
The error logs in 'Cloudwatch' just shows the console.log statements before and after queries and the function terminates with timed out error. I could not figure out the issue.
I have attached the example 'handler.js' code below:
var { Pool, Client } = require('pg');
export function apiTest(event, context, callback) {
var connectionString = 'postgresql://username:password#database.server.com:xxxx/dbname';
var client = new Client({
connectionString: connectionString,
})
client.connect();
console.log('Connected to PostgreSQL database');
client.query('SELECT * from table', (err, res) => {
console.log("inside query");
var jsonString = JSON.stringify(res.rows);
var jsonObj = JSON.parse(jsonString);
const headers = {
"Access-Control-Allow-Origin": "*",
"Access-Control-Allow-Credentials": true
};
// Return status code 500 on error
if (err) {
const response = {
statusCode: 500,
headers: headers,
body: JSON.stringify({
status: false
})
};
callback(null, response);
client.end();
return;
}
const response = {
statusCode: 200,
headers: headers,
body: JSON.stringify(jsonObj)
};
callback(null, response);
console.log("query success")
client.end()
context.succeed(context);
})
}