This article goes over how to increase PostgreSQL max_connections and shared_buffers in a GitHub Actions workflow.

Prerequisites

Set up Postgres in GitHub Actions so your workflow looks like:

# .github/workflows/postgres.yml
on: push
jobs:
  postgres:
    runs-on: ubuntu-latest
    services:
      postgres:
        image: postgres
        env:
          POSTGRES_PASSWORD: postgres
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
          --name my_postgres_container
        ports:
          - 5432:5432
    env:
      PGHOST: localhost
      PGUSER: postgres
      PGDATABASE: postgres
      PGPASSWORD: postgres
  steps:
    - name: Install psql
      run: |
        sudo apt-get update
        sudo apt-get install --yes postgresql-client

Steps

SSH into the Docker container and edit the PostgreSQL config file:

- name: Increase max_connections and shared_buffers
  run: |
    docker exec -i my_postgres_container bash << EOF
      sed -i -e 's/max_connections = 100/max_connections = 1000/' /var/lib/postgresql/data/postgresql.conf
      sed -i -e 's/shared_buffers = 128MB/shared_buffers = 2GB/' /var/lib/postgresql/data/postgresql.conf
    EOF

max_connections was increased from 100 to 1000 and shared_buffers was increased from 128MB to 2GB.

To find the PostgreSQL config file, run:

- name: Show PostgreSQL config file
  run: psql -c 'SHOW config_file;'

Restart the container so the changes can take effect:

- run: docker restart --time 0 my_postgres_container

If you need to connect to the database immediately, add a timeout to wait until it’s up again:

- run: sleep 5

Verify database’s max_connnections has increased to 1000:

- run: psql -c 'SHOW max_connections;'

See example workflow.