Does Postgres Scale?
Key takeaways
- In this blog post, we benchmark the scalability of a single Postgres server.
- We find that Postgres scales even better than we expected: a single server can support a sustained throughput of 144K writes per second, or process 43K workflows per second.
- All experiments were conducted on an AWS RDS db.m7i.24xlarge instance with 96 vCPUs, 384 GB of RAM, and 120K provisioned IOPS on an io2 volume.
When building a durable workflow execution system on Postgres, one of the most common questions we get is “does Postgres scale?” There are plenty of posts from top tech teams asserting that Postgres does scale, but not all show how its performance scales in practice.
In this blog post, we benchmark the scalability of a single Postgres server. We focus on the performance of Postgres writes as those are the bottleneck in workflow execution: a durable workflow has to write to the database multiple times to checkpoint its inputs, its outcome, and the outcome of each of its steps. First, we measure raw Postgres write throughput in a vacuum. Then we analyze the performance of two durable workflow workloads: one that starts workflows locally, and one that uses a Postgres-backed queue.
We find that Postgres scales even better than we expected: a single server can support a sustained throughput of 144K writes per second, or process 43K workflows per second. That translates to 12 billion writes or 4 billion workflows per day, more than enough for most use cases.