This is a companion discussion topic for the original entry at https://www.rstudio.com/blog/pool-0-1-3
The pool package makes it easier for Shiny developers to connect to databases. Up until now, there wasn’t a clearly good way to do this. As a Shiny app author, if you connect to a database globally (outside of the server function), your connection won’t be robust because all sessions would share that connection (which could leave most users hanging when one of them is using it, or even all of them if the connection breaks).