[nrdvana]

The most common design for a Web app on Linux in the last 20 years is to have a pool of worker processes, each single-threaded and ready to serve one request. The processes might be apache ready to invoke PHP, or mod-perl, or a pool of ruby-on-rails or perl or python processes receiving the requests directly. Java tends to be threads instead of processes. I've personally never needed to go past about 100 workers, but I've talked to people who scale up to thousands, and they happen to be using MySQL. I've never used pgbouncer, but understand that's the tool to reach for rather than configuring Pg to allow thousands of connections.