[mapserver-users] long expression statement doesn't workanymore

[Steve Lime]

I was just checking out Rafael's test case. I thought it might be a lexer buffer length
issue but at lease with my version of flex the entire expression string gets loaded. In
the test case the expression is 23K long, a good test.

Further testing shows the problem is in the parser (bison). It seems to have a maximum
token size of 1024 (including \0) so anything after character 1023 is truncated.

Now, how to fix...

Steve

>>> "Worth Lutz" <wal3 at mindspring.com> 11/12/09 4:22 PM >>>
Steve,

Did the test case Rafael Szajbel sent you which show this problem?  I now
have a major problem in my new PHP mapscript application with this.  I can
get lots of parcels selected but once the number gets over about 94 with
each parcel id being 10 characters long, I start loosing the end.  I can
confirm that the last ones are missing.  My test case does not work for
postgres layers or shapefiles so the problem must be in the expression
handling on mapserver.  I am inserting a class in my layer and setting the
expression in the form "([tag]' in '1324567543,1234567645,8766544444')".
Once I exceed a certain limit, parcels are not being highlighted.

I think I could peel out a test case if you have not seen it yet.

-----Original Message-----
From: Steve Lime [mailto:Steve.Lime at dnr.state.mn.us] 
Sent: Friday, October 23, 2009 3:34 PM
To: 'Mapserver Mailinglist ENG'; Worth Lutz; 'Rafael Szajbel'
Subject: RE: [mapserver-users] long expression statement doesn't workanymore

As I mentioned earlier, I'd love a test case!

>>> On 10/23/2009 at 1:28 PM, in message
<2001F78572A34911ACFBA0BF7CD874CC at Worthlaptop>, "Worth Lutz"
<wal3 at mindspring.com> wrote:
> I'm seeing the same (or similar) problem.
> 
> First I query a MSsql database and get a result set.  The parcel ids from
> the result set are inserted into an expression in a class which is
inserted
> into a layer of the map which has its geometry data in a postgres
database.
> (Don't ask why two databases!  We hope to move the data soon.)  The
parcels
> are then highlighted on the map.
> 
> The problem we are seeing is when there are lots of parcels, the resulting
> map has missing parcels in the highlighted set.  My solution to this was
to
> reduce the number of parcels in each class to 100 and insert many
identical
> classes.  My results seem more stable but I still have and error when the
> number of parcels exceeds 500 or so.  Each parcel id is 9 characters long
> and the form of expression is "([tag] in '123456789,987654321')"
> 
> 
> 
> -----Original Message-----
> From: mapserver-users-bounces at lists.osgeo.org 
> [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Steve Lime
> Sent: Wednesday, October 21, 2009 11:20 AM
> To: Mapserver Mailinglist ENG; Rafael Szajbel
> Subject: Re: [mapserver-users] long expression statement doesn't work
> anymore
> 
> Any chance you could create a simple test case showing the problem? The
fact
> it shows some
> features is puzzling. If it was just a matter of the expression getting
> truncated then you should
> see an expression parse error.
> 
> Steve
> 
>>>> Rafael Szajbel <szajbel at widemann.de> 10/21/2009 6:58 AM >>>
> Hello,
> 
> in an older MapServer version (4.10.0) it is possible to use a very long
> Expression or Filter statement.
> 
> Like this one with over 1000 comma separated values:
> 
>       EXPRESSION ('[NR]' IN 'ID1,ID2,.................,ID1100')
> 
> This works fine:
> 
> With newer MapServer versions (whether cgi (expression in mapfile) or
> phpmapscript (expression set with setExpression)) like 5.2.1 or 5.6.0
beta3
> only o small part of the polygons appears:
> 
> 
> So is there a limit on expression statement since version 5?
> There are no errors in the log-file with debug set to 5.
> 
> This is my layer definition:
> 
>   LAYER
>          DATA "shapes/fs.shp"
>          NAME "FS"
>          STATUS ON
>          TYPE POLYGON
>          CLASS
>               NAME "FS"
>               EXPRESSION ('[NR]' IN
> 'ID1,ID2,.............................,ID1100')    # <-- of course without
> the points ;)
>               STYLE
>                     COLOR 255 255 200
>                     OUTLINECOLOR 0 0 0
>              END
>         END
>   END
> 
> Thanks for any hint.
> 
> Rafael
> 
> PS: It is not possible to classify on attributes.  
> 
> 
> 
> 
> 
> 
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