Scaling the GitLab database

This post details the implementation of connection pooling using pgbouncer to address high database connection loads on GitLab.com. It explains the problems with direct PostgreSQL connections, the benefits of connection pooling, and the decision-making process between pgbouncer and pgpool-II. The post highlights the configuration of pgbouncer for transaction pooling, the reduction in `max_connections`, and the setup of separate pools for web requests and background jobs. It also discusses the side effect of disabling prepared statements and the resulting memory savings.