[Libreoffice] Calc need too much RAM to open large spreadsheets than Excel, fix?

[Markus Mohrhard]

Hello,

I have been working a bit on performance related calc problems for 3.5.

I have at least one item left for 3.5: for nearly every undo step we create
a full copy of the whole document. For 3.5 I planned to improve the undo
code for sheets that means that we no longer copy every sheet to an undo
document which is insane. If I have a good idea i might as well have a look
at the undo code for a single sheet. I hope that there is a better solution
than to copy the whole content of a sheet to a new sheet.

Then we have of course a little problem with columns. We create for every
sheet 1024 ScColumns and ScAttrArray even if we don't need them which needs
some memory. I think I did some profiling and a single sheet needs about
150kB on a 64bit computer.

These are at least two problems I know, but we have for sure several other
problems too.

Regards,
Markus

2011/7/27 Kevin Hunter <hunteke at earlham.edu>

> At 6:07am -0400 Wed, 27 Jul 2011, Michael Meeks wrote:
>
>> On Wed, 2011-07-27 at 16:12 +0700, Samphan Raruenrom wrote:
>>
>>> Is there any work on LibreOffice to reduce memory usage of
>>> LibreOffice Calc on large spreadsheets?
>>>
>>
>> but IMHO -the- fundamental design problem with calc, is something
>> quite banal - the concept that a spreadsheet is built from cells:
>> without breaking that basic misconception I don't think we can do
>> any of the really interesting space / time optimisations we need to
>> do.
>>
>
> Can you elaborate a little on this fundamental design flaw?  As a naive and
> unfortunately focused elsewhere personality, I don't immediately know of a
> better model for creating a spreadsheet.  Is it "just" a problem of
> sparsity?  Or is there a much more sophisticated method for memory sharing
> of various similar cell attributes, perhaps analogous to CSS?
>
> Thanks,
>
> Kevin
>
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