Arch Linux

Summary and Info:
Pacman (or man) automatically detects and updates man pages installed to /usr/man but not man pages to /usr/share/man. Arch Linux does not use /usr/man.

Pacman must run "mandb -q" when any number of packages install, remove, or change any man file. Pacman must not run "mandb -q" if all man page changes are found to be identical as many updates are likely to be. Pacman must not run "mandb -q" more than once no matter how many packages installed at the same time make changes to man pages. Having each installer run mandb separately without knowing whether the new files are different from the old files is not an appropriate solution.

This might be a man install options bug.

On rare occasion I've had a newly installed Arch Linux fail to show most man pages until "mandb" is run.

Steps to Reproduce:
Make a package that installs a man page to /usr/man without a "mandb -q" in the .install.
Install package
man -k <keyword>
Remove package
man -k <keyword>
# The man page keyword search will correctly reflect the presence or absence of the package.

Now make a package as above but to /usr/share/man. The keyword search will fail to show newly installed man pages or continue to show recently removed man pages until "mandb -q" is run.