Cloudflare has published the source code for its own edition of the PgBouncer proxy server, which is used to maintain a pool of open connections to the PostgreSQL DBMS. PgBouncer allows applications to access PostgreSQL through already established connections to eliminate the constant execution of resource-intensive repetitive opening and closing of connections and reducing the number of active connections to PostgreSQL.
The changes proposed in the fork are aimed at stricter resource isolation at the level of individual databases (CPU load, memory consumption, and I / O intensity) and providing a limit on the number of connections in relation to the user and connection pool. For example, the published fork implements the ability to limit the size of the connection pool for each user, which works correctly in configurations with host-based authentication (HBA). In addition, support has been added to dynamically change the limits on the number of connections from each user, which allows more flexibility to cut users who send many resource-intensive requests.
Source: opennet.ru