10.2. Database connection pooling

Red Hat Quay is composed of many different processes which all run within the same container. Many of these processes interact with the database.

Database connection pooling is enabled by default, and each process that interacts with the database contains a connection pool. These per-process connection pools are configured to maintain a maximum of 20 connections. Under heavy load, it is possible to fill the connection pool for every process within a Red Hat Quay container. Under certain deployments and loads, this might require analysis to ensure that Red Hat Quay does not exceed the configured database’s maximum connection count.

Overtime, the connection pools release idle connections. To release all connections immediately, Red Hat Quay requires a restart.

If database connection pooling is enabled, it is possible to change the maximum size of the connection pool. This can be done through the following config.yaml option:

# ...
DB_CONNECTION_ARGS:
  max_connections: 10
# ...

$ sudo podman run -d --rm -p 80:8080 -p 443:8443  \
   --name=quay \
   -v $QUAY/config:/conf/stack:Z \
   -v $QUAY/storage:/datastorage:Z \
   -e DB_CONNECTION_POOLING=false
   registry.redhat.io/quay/quay-rhel8:v3.12.1