ConnectionTimeoutMillis is not respected and pool.connect hangs indefinitely  #3197

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1. pcan commented on Aug 29, 2024

   

   pcan

   on Aug 29, 2024

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   Hi, we are probably experiencing the same issue with digitalocean URLs like this: postgresql://user:pass@instancename.h.db.ondigitalocean.com:25060/foobar?sslmode=require.

   We are not able to reproduce it in our dev environment, but in our production env (running on CloudFlare durable objects), it seems to hang quite consistently on the client.connect() (we're not using pools, btw).
2. clintonb commented on Jul 27, 2025

   

   clintonb

   on Jul 27, 2025

   Last edited by clintonb

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   I'm facing a similar issue. The time out is supposed to be 30 seconds, but I have traces that go on for 30 minutes. They typically have the following spans:

   pg-pool.connect
   └── pg.connect
       └── tcp.connect
           └── dns.lookup
   

   I'm still trying to figure out why GKE DNS is so broken; however, I would still expect the connection timeout to kick in and kill this attempt.

   P.S. This may be a duplicate of #2338.
3. hjr3 commented on Jul 27, 2025

   

   hjr3

   on Jul 27, 2025

   Collaborator

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   I'm still trying to figure out why GKE DNS is so broken

   k8s DNS has some real problems. bdeitte/hot-shots#223 may be helpful to read

   you may want to consider caching DNS queries

   Example:

   const dns = require('dns');
   const net = require('net')
   
   const { Client } = require('pg');
   
   const run = async () => {
       const stream = await (new Promise((resolve, reject) => {
           const socket = net.connect({
               host: 'localhost',
               port: 5432,
               lookup: (hostname, options, callback) => {
                   // write your custom DNS lookup logic here
                   dns.lookup(hostname, options, callback);
               },
           }, () => {
               resolve(socket);
           });
   
           socket.on('error', (error) => {
               reject(error);
           });
       }));
   
       const client = new Client({
           stream,
           database: 'dbname',
           user: 'user',
           password: '',
       });
       
       await client.connect();
   
       client.end();
       stream.end();
   };
   
   run().catch(err => {
       console.error('Connection error', err.stack);
   });
4. DijieDeng

   added a commit that references this issue on Jul 28, 2026

   fix(pg-pool): honor connectionTimeoutMillis and prevent connection le…

   ...

   30dfe3f
5. DijieDeng commented on Jul 28, 2026

   

   DijieDeng

   on Jul 28, 2026

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   I've opened #3721 with a fix for this. It addresses the root cause in pg-pool's newClient(): the connectionTimeoutMillis timer previously only tore down the connection under specific conditions (client.connection existed or !client.isConnected()), so when neither held — e.g. during a slow/stalled DNS lookup — the timer fired but did nothing and pool.connect() hung forever. The fix makes the timeout always reject the checkout at the deadline (preserving the native-client exemption), removes the client from the pool, and ends the connection cleanly. It also discards connections that finish establishing after the timeout, which closes the related connection leak (#3543). A regression test is included.