Re: [graphviz-interest] Dot extremely slow when called from python cgi script

[Dan Yamins <dyamins@xxxxxxxxx>]

I'm having a problem with performance of the program "dot" (for
rendering graphs) when called from a python cgi script, served by an
apache virtual host.  I'm writing this email both the apache httpd list
as well as the graphviz users lists (hoping some intersection might be
useful).   

I'm using OSX 10.5.6 and graphviz2.22 (built via macports). 

When
I run a simple python script that calls dot (via a system call) to
render a small graph, it takes about .04 seconds, which is normal.  But
when I run the same call via CGI script it takes roughly 100 times
longer (4 seconds).     I've tried graphs of various sizes, ranging
from very tiny graphs (4 nodes) to much larger graphs.   The 4 seconds
figure for the CGI script doesn't change much except for very large
graphs, so the time spent in the CGI script is probably not coming from
the actual rendering itself.

I posted this problem some weeks ago on these lists, and got the following enlightening response:

>A hunch is that some cache is not seen or
is not
available. 
>Could be the fontconfig cache.  It could be the case that you 
>have a ~dyamins/.fontconfig but httpd is not able to create one 
>and there is no system cache. 

This did indeed seem to be the problem.  I wrote back:

> I do have a
~/.fontconfig directory containing cache files.  When I delete it, the
performance of the command line script is just as slow as the cgi
> script until the next time the command is run (e.g. after the cache is
remade).    So I  guess the question becomes: how do I get apache and
the > CGI script to see and use the .fontconfig caches?

However, I never received an answer about about how to get apache to see the .fontconfig caches.   

Any thoughts would be really appreciated. 

Thanks,
Dan