Is there a way to, on Map/Reduce scripts, to somehow use global variables? I have to do a search lookup every time I hit inside a reduce, and really this only needs to happen once. So if I have 5000 entries, I have to query the db 5000 times

You can set a script parameter and use that as a global variable. I do this on a map reduce i use that saves files to a folder with the name of that day/month. In my get input data i create the folder and set a script parameter to the folders id which i can then use in my map or reduce

N/cache

?