“mod_perl,” o’course, “is a very different kettle o’ fish,” because of its inherently persistent nature as an integrated part of the long life of the web-server process(es).

As mentioned in http://modperlbook.org/html/20-1-1-Apache-DBI-Connections.html (for example...) database handles routinely get special treatment in the mod_perl environment, and these treatments are more-or-less designed to ignore exactly what you do.

Nevertheless, in writing my original code, for whatever environment, I do try to follow this gentlemanly maxim:   “Be tidy.   Wipe the toilet seat.   Flush.   Lower the lid for the next lady.”   Whatever you open, close.   Don’t throw your trash on the ground and expect some faceless public worker to clean up after you.   More-reliable code will be your reward.