Re: CSV files : huge performance issue...

[Jody Goldberg <jody gnome org>]

On Fri, Nov 12, 2004 at 07:24:07PM +0100, Emmanuel Pacaud wrote:
> > 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.

This is likely caused by disregarding the 'rubber_band_directly ==
FALSE' flag for plots.  When moving/resizing the plots we would end
up redrawing them with motion rather than using a rubber banded
rectange and redrawing on completion.  That was fixed in 1.3.9[2-3].
 
> > 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 ?
I do not understand.

> > Also, saving the file into
> > Gnumeric format took about 5 to 10 minutes of hard work for the hard
> > drive... :-/

The 1.4.0 will use the new faster sax based exporter for .gnumeric
files.  That is a huge speed win.  1.2.x used the original xml DOM
based implementation that did not scale well at all.  Unfortunately
we are still using the xml DOM based importer.  There is a sax
importer, which is significantly faster than the default, but it
does not support sheet objects yet (charts, comments, drawings ...).

> > 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...

We take performance seriously but can't catch everything before we
release.  As we find problems, and when people report them we can
solve them.