7.18.2: "Connection terminated unexpectedly" when using client.query with a pool when pool has been idle for 10 minutes (running in AWS Lambda)

Code is running in a lambda. When we run the function below it runs fine. But if we run it and then wait 10 minutes then run it again, we get an error every time. We are querying Aurora Postgres on AWS.

Code:

const {Pool} = require('pg');

// Global Connection, can be re-used!!
const pgPool = new Pool({
    user: process.env.PG_USER,
    host: process.env.PG_HOST,
    database: process.env.PG_DATABASE,
    password: process.env.PG_PASSWORD,
    port: process.env.PG_PORT,
    max: process.env.MAX_CLIENTS
});

pgPool.on('error', (err, client) => {
    console.error('Unexpected error in Postgress connection pool', err);
});

async function performQuery(event) {

    let queryString = null;
    let args = null;

    try {
        // some setup code here...  
        const client = await pgPool.connect();
        try {
            const res = await client.query(queryString, args);
            return res.rows;
        } finally {
            client.release();
        }
    } catch (err) {
        console.error('Problem executing export query:');
        console.error(err); // <-- this line is in the log below  
        throw err;
    }
}

This is what I see in the cloudwatch logs:

{
    "errorType": "Error",
    "errorMessage": "Connection terminated unexpectedly",
    "stack": [
    "Error: Connection terminated unexpectedly",
    "    at Connection.<anonymous> (/var/task/node_modules/pg/lib/client.js:255:9)",
    "    at Object.onceWrapper (events.js:312:28)",
    "    at Connection.emit (events.js:223:5)",
    "    at Connection.EventEmitter.emit (domain.js:475:20)",
    "    at Socket.<anonymous> (/var/task/node_modules/pg/lib/connection.js:78:10)",
    "    at Socket.emit (events.js:223:5)",
    "    at Socket.EventEmitter.emit (domain.js:475:20)",
    "    at TCP.<anonymous> (net.js:664:12)"
]
}

I’ve tried a few variations on this but the constant is the 10 minutes and the use of the Pool. To me this code is almost identical to the code in https://node-postgres.com/features/pooling.

So far it looks like the problem has been solved by using a Client instead:

const client = new Client({
            user: process.env.PG_USER,
            host: process.env.PG_HOST,
            database: process.env.PG_DATABASE,
            password: process.env.PG_PASSWORD,
            port: process.env.PG_PORT
        });

        await client.connect();
        const res = await client.query(queryString, args);
        await client.end();
        return res.rows;

[Dakuan]

still a thing

[vitaly-t]

People praise AWS Lambda, without knowing that it is the only hosting environment in the world that implements aggressive connection-recycle policy.

Nobody it seems is greedy enough as to inconvenience their clients so bad, to decide to drop live connections instead of what everyone else is doing - extending the IO capacity. It’s just dumb corporate greed, backed up by self-assured market dominance, to maximize profit by reducing the cost, without increasing the capacity.

That’s why issues like this one keep polluting the Internet. That’s why I do not use AWS Lambda.