postgresql-simple v0.4.3.0 Release Notes
Release Date: 2014-07-10 // almost 10 years ago-
connect and exec now use libpq asynchronously on non-Windows platforms. This means we are using threadWaitRead and threadWaitWrite to have GHC's IO manager schedule non-blocking C calls to libpq, instead of using blocking C calls and having the OS kernel do the scheduling. Among other things, this now means that System.Timeout will work with connect and exec on unix platforms.
connect and exec now throw IOErrors instead of SQLErrors in some cases. The intention is for SQLErrors to represent an error returned by the server, and to use IOErrors for errors that originate from client-side code. However, this goal isn't perfectly achieved as of yet.