Cleaning the /tmp directory

[Ken Lord]

Hi Ed,
 I pursued my MODE=MAP issues a little deeper ... the new hardware didn't 
fix it ... 
 My snapshots fail sporadically. If i plug the source of the images into a 
new webpage, I get the following error: "CGI error, The specified CGI 
application misbehaved by not returning a complete set of HTTP headers.". 
Sometimes the top half of an image generates, but not the rest.
 Ive seen this error before when using a faulty build of mapserver that was 
up on the homepage for awhile a couple months ago but in that case it 
affected all maps generated, not just some of the snapshots. 
 My current install is clean on a new server, 4.4.2 and 4.6b2. Each install 
is in its own folder, to keep the dll's of the different versions separated, 
the website has a virtual directory that points to the specific version I 
want it to use. My mode=browse maps work fine.
 The failures happen often on the same features, or in the same area of one 
feature while another area works. The features pass as valid to PostGIS, 
using shapefiles made no difference. The number of features returned does 
not seem to be impacting the occurance of failures.
 These failures have been happening since MapServer 4. I may need to rig up 
mapserver 3.6 to produce the snapshots since it never gave me a problem. 
Anyways maybe this shows why I was leery to suggest to the other person to 
rely on mode=map.
 Cheers,
Ken Lord
Vancouver BC
 On 5/24/05, Ed McNierney <ed at topozone.com> wrote: 
> 
> Ken -
>  If you are trying to serve multiple simultaneous requests, with 
> everything competing to write and then read files from the temp directory, 
> the disk I/O to that drive can become a *serious* bottleneck. If heavy 
> usage is not a concern, then this may be a non-issue.
>  I have never seen failures due to MODE=MAP (rather than being caused by 
> something else) and I've used it about a billion times (literally <g>). I 
> would be leery of blaming failures on MODE=MAP without some diagnosis about 
> the cause.
>   - Ed
>  
> Ed McNierney
> President and Chief Mapmaker
> TopoZone.com <http://topozone.com/> / Maps a la carte, Inc.
> 73 Princeton Street, Suite 305
> North Chelmsford, MA 01863
> ed at topozone.com
> (978) 251-4242 
> 
>  ------------------------------
> *From:* UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] *On 
> Behalf Of *Ken Lord
> *Sent:* Tuesday, May 24, 2005 12:48 PM
> *To:* MAPSERVER-USERS at LISTS.UMN.EDU
> *Subject:* Re: [UMN_MAPSERVER-USERS] Cleaning the /tmp directory
> 
>   James,
>  I use the method you mentioned, 'MODE=MAP', to generate snapshots for 
> query results. It works great to highlight each individual item returned by 
> a map query, placed next each item's attributes.
>  However, Since mapserver 4 and later have come out, often the images fail 
> despite the log statement of 'normal execution'.
>  I have simplified the maps as much as possible, and I'm sure that its not 
> a lingering syntax difference between 3.6 (where it worked great) and 4 or 
> later. The failures are not consistant either. Why they don't either all 
> work or all fail, or at least all the same features queried fail 
> consistantly? I have no idea. 
>  So I'm leary about suggesting people use MODE=MAP for all their maps just 
> to keep their temp folder's empty, especially when a simple .bat file can be 
> used to empty them regularly.
>  Cheers,
> Ken Lord
> Vancouver BC
>
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