I was introduced to AOLServer and OpenACS in 2002 by a close friend who I grew up with. We built a very robust application architecture over the course of the following 6 years.
PostgreSQL was sitting behind the AOLServer/OpenACS instance and AOLServer nicely managed the database connection pools. AOLServer is multi-threaded and internally handles TCL interpretation and execution. TCL makes heavy use of lists (implementation notes aside), so many LISP programmers have enjoyed working with it.
The OpenACS developer toolbar is a tool that provides developers with access to various debugging and profiling information about their OpenACS application. It is a feature that is built into the OpenACS application framework and can be enabled or disabled depending on the needs of the developer.
Once enabled, the developer toolbar is accessible via a web browser and provides a range of information about the current page, including SQL queries, response times, and server resources. This information can be used to optimize and debug an OpenACS application, allowing developers to quickly identify and fix performance issues.
The OpenACS developer toolbar is just one of the many tools available to developers using the AOLServer, OpenACS, PostgreSQL, and TCL stack. Together, these technologies provide a fast, high-performance, database-driven application architecture that supports rapid development.