[thredds] over written file has old global attributes

Tue Nov 6 10:35:02 MST 2007

It's not a browser caching problem. I have a very old LAS that accesses 
these files. From the LAS, input for a model run is set up then a servlet 
is run on 1 of several possible machines that starts a FORTRAN model run 
that overwwites files so that the LAS interface has static files/"DODs" 
URLs for the output. We are moving to different code but need to keep this 
working until the new is up and reliable. The data updates, I can see 
that in the plots, but I use global attributes in labeling and I get the 
old information sometimes, 2 out of 31 SIM runs. The example I put out on 
the sift machine was run on an internal machine and then sftp-ed to sift. 
Then I made another run and again sftp-ed it to the sift machine and saw 
the same "old attributes" problem, which I really didn't think I would. 
If tomcat is restarted then I get the new information so I imagine it is 
some caching problem. I did try removing the file before rerunning the 
SIM and that did not solve the problem. Is there some way to turn off 
caching of metadata so the file is checked every time it's accessed? Jean
  ___________________________________________________________
   Jean Newman                             Tel: 206-526-6531
   NOAA Center for Tsunami Research
   NOAA/PMEL/OERD2 - UW/JISAO              FAX: 206-526-6485
   7600 Sand Point Way NE, Bldg. 3    jean.c.newman at noaa.gov
   Seattle, WA 98115-6349               jcn at u.washington.edu
  _________________________. URL: http://nctr.pmel.noaa.gov/
                          (__________________________________

On Tue, 6 Nov 2007, John Caron wrote:

> The other possibility is caching in your browser. It can be tricky to 
be absolutely sure you are getting a fresh copy. I like using the "Live 
HTTP Headers" plugin for firefox. But perhaps Shift-Refresh might work 
also. An independent test is the ToolsUI application, which never caches:
>
> 
http://www.unidata.ucar.edu/software/netcdf-java/v2.2/webstart-dev/index.html
>
> If you still see the problem, then it is caching on the server. It 
occurs to me that "overwriting the file" may be the problem. You should 
be writing a new file, and deleting the old. What exactly are you doing?
>
> Roy Mendelssohn wrote:
>> Hi jean: '
>>
>> My guess is you are getting the cached information, which hasn't been
>> updated.  You can set the frequency of update in the catalog xml
>> file.  Also, usually if you touch the file  (i.e. do something that
>> causes to Thredds to access the data( that  usually also updates the
>> info.
>>
>> -Roy M.
>>
>>
>> On Nov 5, 2007, at 4:51 PM, Jean.C.Newman at noaa.gov wrote:
>>
>>> I have a set of netcdf files that are being accessed via OpenDAP
>>> and are
>>> regularly overwritten. Most of the files, 29 sets of 31, update
>>> correctly
>>> but in 2 file sets the "Global Attributes" don't update to the new
>>> information although the "data" does. "ncdump -h" shows the correct
>>> information, :history = "MOST v2.080 11-05-2007  16:09:22" ;
>>>               :title = "Aleutian-Cascadia: Mwt 8.4, 21.00*b65" ;
>>>   in the headers but when I look at it in a browser,
>>> http://sift.pmel.noaa.gov/thredds/dodsC/data/crescent_runup_ha.nc.html
>>> I see the old file attributes,
>>> history: "MOST v2.080 11-05-2007  11:49:33"
>>> title: "Aleutian-Cascadia: Mwt 8.5, 29.00*b25".
>>> If I restart tomcat then the correct information shows up.
>>> I'm new at thredds so I may very well be doing something stupid but I
>>> could find no information. Below is the change I made to
>>> $tomcat_home/content/thredds/catalog.xml. Any suggestion?
>>> Thank you, Jean
>>> <service name="ncdods" serviceType="OpenDAP" base="/thredds/dodsC/" />
>>>    <datasetScan name="MOST tsunami model data" ID="mostDatasetScan"
>>>         path="sims" location="/home/tg15/data/sims"
>>> serviceName="ncdods">
>>>      <metadata inherited="true">
>>>        <serviceName>ncdods</serviceName>
>>>      </metadata>
>>>      <filter>
>>>        <include wildcard="*.nc"/>
>>>      </filter>
>>>      <sort>
>>>        <lexigraphicByName increasing="true" />
>>>      </sort>
>>>    </datasetScan>
>>>   ___________________________________________________________
>>>    Jean Newman                             Tel: 206-526-6531
>>> _______________________________________________
>>> thredds mailing list
>>> thredds at unidata.ucar.edu
>>> For list information or to unsubscribe,  visit: http://
>>> www.unidata.ucar.edu/mailing_lists/
>>
>> **********************
>> "The contents of this message do not reflect any position of the U.S.
>> Government or NOAA."
>> **********************
>> Roy Mendelssohn
>> Supervisory Operations Research Analyst
>> NOAA/NMFS
>> Environmental Research Division
>> Southwest Fisheries Science Center
>> 1352 Lighthouse Avenue
>> Pacific Grove, CA 93950-2097
>>
>> e-mail: Roy.Mendelssohn at noaa.gov (Note new e-mail address)
>> voice: (831)-648-9029
>> fax: (831)-648-8440
>> www: http://www.pfeg.noaa.gov/
>>
>> "Old age and treachery will overcome youth and skill."
>>
>>
>>
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