Pacman DB in tmpfs

/etc/rc.d/pacdbtmp

#!/bin/bash
tmpfs_size=100m
pacman_archive=/var/lib/pacman.tar.gz
pacman_sync=var/lib/pacman/sync
[ -d /$pacman_sync ] || mkdir /$pacman_sync
mounted=$(grep -c /$pacman_sync /proc/mounts)
case "$1" in
  stop)
    [ $mounted = 0 ] && exit 1
    umount /$pacman_sync
  ;;
  start)
    [ $mounted -gt 0 ] && exit 1
    creates=$(ls -1 /$pacman_sync)
    mount -t tmpfs tmpfs -o size=$tmpfs_size /$pacman_sync
    for create in $creates ; do
      mkdir -p /$pacman_sync/$create
      [ -f /$pacman_sync/../${create}.db.tar.gz ] && tar -C /$pacman_sync/$create/ -xzf /$pacman_sync/../${create}.db.tar.gz
    done
  ;;
  restart)
    $0 stop
    $0 start
  ;;
  *)
    echo "start or stop"
  ;;
esac

Finally modify your daemons list.

DAEMONS=(syslog-ng pacdbtmp...)