Knex: Timeout acquiring a connection. The pool is probably full. Are you missing a .transacting(trx) call? [2024]

Question

I'm encountering a KnexTimeoutError when attempting to deploy my Node.js application's database changes using a series of npm scripts that utilize Knex migrations. My goal is to rollback all migrations, apply the latest migrations, and then seed the database, executed in a single npm command. The specific command I'm running is,

"deploy:fresh": "npm run knex:migrate:rollback:all && npm run knex:migrate:latest && npm run knex:seed:run"

I have been running this command quite a lot of times during development.

My stack,

• NestJS
• Objection.js ORM (with knex.js)
• PostgreSQL (on Supabase)

I know a similar alternative question (Knex: Timeout acquiring a connection. The pool is probably full. Are you missing a .transacting(trx) call?) exists, but it's too old and the versions suggested are too old for me now.

• "knex": "^3.1.0"
• "objection": "^3.1.4",
• "pg": "^8.11.3",

Answer 1

We would need to see your knex settings. In the connection object, there are (optional) settings for the connection pool.

{
  ..., // the rest of the settings
  pool: { min: 1, max: 20 },
}

You could try to up the max to something than the default, which is 10. But you should know that something in your script is likely a bit unhealthy if it eats up all those connections. This is more of a plaster than a remedy...

Btw, make sure that the connection to the db works in the first place so that is not the issue.