Description:
Undo information for large spreadsheets is memory consuming

Steps to Reproduce:
1. Open attachment 159234 [details] (bug 131791). Preferably after bug 131791 is fixed, it's slow as hell at this point
2. Drag columns the different columns to left right (and monitor CPU usage). It will bump nearly every time with 200-300 MB or so. 

Actual Results:
Memory usage increases with 200-300 MB for every change made, caused by undo information (Tools -> Options -> LibreOfficeDev -> Advanced -> expert configuration -> Search for Undo and set 100 steps back to 0)

Expected Results:
I'm guessing the actually result are always stored as undo information. I would be more efficient to store - if possible - only the formula itself. At least for F-J columns.

This is probably a complicated matter. As there are cells / columns/ rows with pure 'data' (like column A/B). Cells/ columns/ rows/ with formula's and 'data' combined. And cells/columns/rows with only a formula.  

So extensive strategic optimization will probably make debugging harder and maybe introduce new (case depended) bugs, which are hard to track down. However, there must be some basic strategy's to make this more workable. 

Especially with the amount of rows/columns/sheets allowed. 

Other solutions:
- Reduce undo count for Calc in general or for large sheets 
- Ask if undo information should be stored for large operations 


Reproducible: Always


User Profile Reset: No



Additional Info:
Version: 7.0.0.0.alpha0+ (x64)
Build ID: 4501a0ba623ad61c5a4e0b807da2e96f0e4ce82c
CPU threads: 4; OS: Windows 6.3 Build 9600; UI render: default; VCL: win; 
Locale: nl-NL (nl_NL); UI-Language: en-US
Calc: CL