[Mapserver-users] Large Map Files

[C F]

As far as XML goes... I think the performance issues can be handled by 
serializing (pre-parsing) the xml files into object files.  In theory, that 
would be even faster than the current approach.  Of course then you would 
have to deal with synchronization which might be just a matter of looking at 
a timestamp on a file.
Anyway... I'm not pushing for this.. I just wanted to comment on the xml 
performance comments.  I've kind of started down the XML route on my own by 
building an xml schema and a stylesheet to translate XML docs to mapfiles.  
I have a feeling there are similar efforts underway.  If anyone is doing so 
and feel like collaborating, please let me know.


>From: Richard Greenwood <Rich at greenwoodmap.com>
>To: "Steve Lime" <steve.lime at dnr.state.mn.us>
>CC: mapserver-users at lists.gis.umn.edu
>Subject: Re: [Mapserver-users] Large Map Files
>Date: Tue, 11 Feb 2003 20:06:51 -0700
>
>I agree with your point that easing management should not be at the expense 
>of performance, but how much of a hit do you really think it would be? I 
>figure the file system would probably cache the map file(s) because they 
>are small and getting read with every hit. The total size it's going to be 
>any different (as opposed to rather verbose XML). And if you didn't want to 
>use includes you'd just blow them off with no performance penalty.
>
>On the other had, you have mentioned a mapserver specific preprocessor in 
>the past, which could potentially answer both issues: convenience with 
>includes or XML, and performance by "pre-parseing" the map file. Are you 
>thinking of something like make that would be invoked by mapserver each 
>time, or a utility that was executed manually? How much performance 
>advantage could be achieved by "pre-parseing" the map file?
>
>Rich
>
>At 08:40 PM 2/11/2003 -0600, you wrote:
>
>>Yup, but is that overhead something we really want to  absorb every time a 
>>map is created (true whether we're talking map files or xml)? A 
>>pre-processor that is run as necessary seems more practical. If using the 
>>C pre-processor seems like a kludge then perhaps a tool specific to 
>>MapServer needs building.
>>
>>I worry about the effects of features that ease management headaches at 
>>the expense of performance. Which is more important? I agree that 
>>segmenting configuration into reusable pieces is very important, but does 
>>it have to happen with each rendering of a map?
>>
>>Steve
>>
>>
>> >>> Paul Ramsey <pramsey at refractions.net> 02/11/03 19:29 PM >>>
>>I know nothing about lexers, sadly. However: cannot a relatively
>>substitution routine first convert all the INCLUDE's into their
>>equivalents, then the full parser runs on the final "file"?
>>
>>Steve Lime wrote:
>> > It's been on the todo list for years. Problem is maintaining parser 
>>state over the multiple
>> > files. It's possible to have multiple lexers running within the same 
>>program but not at the
>> > same time. Someone please file this as a feature request...
>> >
>> >
>> >>>>Richard Greenwood <Rich at GreenwoodMap.com> 02/11/03 01:22PM >>>
>> >
>> > At 11:02 AM 2/11/2003 -0800, Paul Ramsey wrote:
>> >
>> >
>> >>I have been thinking that an extremely powerful extension to the .map 
>>file
>> >>would be an "INCLUDE" directive, which reads a map file fragment into
>> >>another map file.  A quick-and-dirty map service could then be 
>>assembled with:
>> >
>> >
>> > An INCLUDE directive would be a wonderful addition!
>> >
>> > Rich
>> >
>> >
>> > Richard W. Greenwood, PLS
>> > Greenwood Mapping, Inc.
>> > Rich at GreenwoodMap.com
>> > (307) 733-0203
>> > http://www.GreenwoodMap.com
>> >
>> >
>> > _______________________________________________
>> > Mapserver-users mailing list
>> > Mapserver-users at lists.gis.umn.edu
>> > http://lists.gis.umn.edu/mailman/listinfo/mapserver-users
>>
>>
>>--
>>        __
>>       /
>>       | Paul Ramsey
>>       | Refractions Research
>>       | Email: pramsey at refractions.net
>>       | Phone: (250) 885-0632
>>       \_
>>
>>_______________________________________________
>>Mapserver-users mailing list
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>>
>>
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>
>
>Richard W. Greenwood, PLS
>Greenwood Mapping, Inc.
>Rich at GreenwoodMap.com
>(307) 733-0203
>http://www.GreenwoodMap.com


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