Hoping someone has some insight into how to improve import performance. I have all my server "max" settings dialed way up. File size, upload size, max execution time is all supersized, but I still have to break my import files down into very tiny chunks to get it to import without hanging. 
I do have a decent number of columns...maybe 30...but I feel like I'm missing something. For example, are there columns I should exclude from my import file because they are being checked line by line like the Key column for example? I have this column, but it is blank so that unique keys are assigned on import. I should imagine this is done whether I have the column in the file or not. 
Also, if I want to update records I know I must include a Key column that matches the existing entry Keys. Do I need to include more columns than that, or can my file include the Key column and the single other column I want to update?
Thanks for any help/insight you have!