I would like to propose a new Big Feature for pacman: a framework for buffering and combining common "bookkeeping" tasks when syncing multiple packages. Based on investigating just one offender, gtk-update-icon-cache, I foresee that implementing this feature will provide an order of magnitude performance boost for -S.

The feature would be opt-in for packages. I suggest a separate program, let's name it pacman-after-sync. Instead of calling gtk-update-icon-cache directly in the install script, the author of the install script would write:

pacman-after-sync -t $TRANSACTION -c gtk-uptade-icon-cache <arguments>

(The $TRANSACTION variable would have been set by pacman). This program would log the command and arguments following the -c switch to some buffer identified by the value of the -t parameter, and then after syncing all packages pacman would issue:

pacman-after-sync -t <the same transaction id> --flush

The new program would then combine identical lines in the buffer identified by the value of the -t parameter and issue each of them once, preserving the order of last occurrence. As an example result, gtk-update-icon-cache would probably be run *once*, not 300+ times, when syncing the whole KDE (provided the maintainer of each package chose to use pacman-after-sync).