[thredds] over written file has old global attributes

Jean.C.Newman at noaa.gov Jean.C.Newman at noaa.gov
Tue Nov 6 13:04:23 MST 2007


On the sift machine, because we were doing testing, we have "opendap" with 
& without thredds and "looking" at the file - ncdump & dncdump with 
"opendap no thredds" both give correct attributes while dcdump with 
"thredds" gives old attribute information. Jean

ncdump -h crescent_runup_ha.nc
...
// global attributes:
                 :history = "MOST v2.080 11-05-2007  16:09:22" ;
                 :title = "Aleutian-Cascadia: Mwt 8.4, 21.00*b65" ;

dncdump -h 
http://sift.pmel.noaa.gov/thredds/dodsC/data/crescent_runup_ha.nc
...
// global attributes:
                 :history = "MOST v2.080 11-05-2007  11:49:33" ;
                 :title = "Aleutian-Cascadia: Mwt 8.5, 29.00*b25" ;

dncdump -h http://sift.pmel.noaa.gov/opendap/crescent_runup_ha.nc
...
// global attributes:
                 :history = "MOST v2.080 11-05-2007  16:09:22" ;
                 :title = "Aleutian-Cascadia: Mwt 8.4, 21.00*b65" ;
  ___________________________________________________________
   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, Jean.C.Newman at noaa.gov wrote:

> One other thing, the "old attributes" lasts. I made a run yesterday at
> 11:23 am and it was over written several time the last at 16:09 and today
> if I look at that output file via LAS/"dncdump -h" it still shows the "old
> stuff" from the 11:23 run. "ncdump -h crescent_runup_ha.nc" has the
> correct 16:09 information. Thanks, Jean
>  ___________________________________________________________
>   Jean Newman                             Tel: 206-526-6531
>
> On Tue, 6 Nov 2007, Jean.C.Newman at noaa.gov wrote:
>
>> The question:
>> 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
>>
>> On Tue, 6 Nov 2007, Jean.C.Newman at noaa.gov wrote:
>>
>>> 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
>>>
>>> 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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