Re: CSV files : huge performance issue...

[Emmanuel Pacaud <emmanuel pacaud univ-poitiers fr>]

Hi,

> First post here, not sure if this is the right place, if it's for
> users or developpers, but I couldn't find a Gnumeric specific web
> forum so here I am.

It's the right place for discussion about gnumeric, for users and
developers.

> I ran into a huge problem today when (trying to) working on a 'CSV'
> file. No problem to import it, works like a charm. However doing
> anything with the data proves EXTREMELY slow. So slow that it's
> actually not useable. My file is not big, only 1 MB, and contains
> about 800,000 cells (40 columns and 20,000 lines), but creating a
> graph takes quite some time, simply getting a preview of the graph
> when clicking on the "preview" button takes 3 to 5 seconds I would
> say. 

If it takes only 3 or 5 seconds, I guess it's a xy plot. Line plots are
slower.

We have a serious performance problem that lies in the use of libart for
rendering. We get nice outputs with it, but it's very slow. We plan to
drop libart for cairo, expecting speed improvement, but currently
performance with a lot of data is rather poor.

> This is fair enough, you only do it once. However once the graph is
> created and put on top of the cells/spreadsheet, if I want to "drag"
> it somewhere with the mouse, it takes about 15 seconds to move by 3 or
> 4 cells...

That's not expected. Each graph are rendered and cached in a pixbuf,
moving them is expected to be quite fast.

Which version do you use ?

What would be great is that you provide us a sample file. Could you open
a new bug against gnumeric/charting in http://bugzilla.gnome.org, and
attach there the sample file ?

> It's as is whatever I am trying to do with the mouse, gnumeric
> processess the entire 800,000 cells, instead of affecting only the 100
> or so cells taht are atually visible at a given time, in the document
> window. Am I right in this assumption ?   Also, saving the file into
> Gnumeric format took about 5 to 10 minutes of hard work for the hard
> drive... :-/
> What puzzles me is that last time I worked on such files, it was with
> MS Excel, and it was lightening fast, opening, creating graphs,
> manipulating data, moving graphs around, saving the file, everytinhg
> seemed fast and effortless. So the machine is not at fault. Why is
> Gnuméric so slow ? Considering Gnuméric aims (I think ?) to be as good
> as Excel, can I hope that this major issue will be investigated, or is
> already under investigation ? 

This issues will surely be investigated...

        Emmanuel.