# Postgres needs built-in connection pooling

- Published: 2021-10-22
- URL: https://notes.webutvikling.org/postgres-should-get-builtin-connection-pooling
- Tags: serverless, postgres, database

The future is serverless, and Postgres has issues fitting into that.

1. The high cost of creating and holding a database connection,
   effectively stop direct connections from serverless functions.

2. The slow startup time eliminates Postgres on-demand service.
   You pay for standby capacity instead.

### Performance issue on multiple clients

Postgres' performance decline rapidly with number of connections.
The cost of holding and creating connections is to an extent solvable
with connection-pooling. Postgres does not have pooling built-in,
but it can be done with software like [pgBouncer](https://www.pgbouncer.org/).

This is what [Digitial Ocean](https://docs.digitalocean.com/products/databases/postgresql/how-to/manage-connection-pools/)
has included by default on its database services. Since connection pooling
is run on separate host, it's not surprising that Digital Ocean charges
[almost twice the amount](https://www.digitalocean.com/pricing) of e.g.
[render.com](https://render.com/pricing/#databases) for a minimal database.

### Paying for capacity

Maybe the biggest issue with paying for initial standby capacity is how
it drives developers away from Postgres and towards other options like
DynamoDB or Firebase. A student or someone playing around with making
an app for fun will often avoid the 10$/month cost. And what you
learn is what you'll preach when starting in a "real" job.

A second issue is scaling, which is particulary relevant for new companies.
Publicity might increase their database load by 100x unexpectedly, and
there isn't really great Postgres services that handle that for you (yet).

## Postgres won't adapt to serverless

I think Postgres is amazing, but I'm a bit worried that it'll become obsolete
over time unless it adapts the the ephemeral function based future.

[Postgres 14](https://www.postgresql.org/about/news/postgresql-14-released-2318/)
goes in the right direction, handles many connections a bit better, but it's still
leap years from NoSQL. Searching ["serverless" on postgresql.org](https://www.postgresql.org/search/?q=serverless)
yield no results, and its [TODO list](https://wiki.postgresql.org/wiki/Todo) neither mentions
connection pooling. We can find the following in its [Number of database connections page](https://wiki.postgresql.org/wiki/Number_Of_Database_Connections) (which is from 2014!):

> The decision not to include a connection pooler inside the PostgreSQL server itself has been taken deliberately and with good reason
> [Postgres, 2014](https://wiki.postgresql.org/wiki/Number_Of_Database_Connections)

### ...but it's maybe not their responsibility?

Postgres is an open source software, not owned by any company. Anyone can set up
a postgres database on their local computer or their server. Cloud providers
like AWS, Google and Microsoft are the ones who would benefit greatly from a
postgres-like serverless service, and maybe it's them who should figure out
how to make that work?

AWS attempts to be doing just that with [Aurora Serverless 2.0 (preview)](https://aws.amazon.com/rds/aurora/serverless/).
It can scale up within milliseconds and automatically scale down when traffic resides.
But its cold start (scaling from 0 capacity) is still so slow it becomes unusable
unless you keep minimum capacity always on (starts at about 100$/month).

The result of all this is alternative database services adapted to a serverless
environment, like [Firestore](https://firebase.google.com/docs/firestore) and [FaunaDB](https://fauna.com/).
While that's cool and all, I'd really like to keep living in a Postgres world.
I'm just not sure I can anymore.

## Related

- [serverless.com: "Choosing a Database for Serverless Applications"](https://www.serverless.com/blog/choosing-a-database-with-serverless)
- [fauna.com: ""AWS Aurora Serverless v2: Architecture, Features, Pricing, and Comparison with Fauna](https://fauna.com/blog/compare-aws-aurora-serverless-v2-architecture-features-pricing-vs-fauna)
- [theburningmunk: "What you need to know about Aurora Serverless v2, so far."](https://theburningmonk.com/2020/12/what-you-need-to-know-about-aurora-serverless-v2-so-far/)
- [jeremydaily: "Aurora Serverless v2: The Good, the Better, and the Possibly Amazing"](https://www.jeremydaly.com/aurora-serverless-v2-preview/)