Hi Rich,
What kind of proxy setup do you have in front of your TDS server? I'm
surprised the proxy doesn't pass along whatever error it gets. Does it
take a while before you get the "Proxy Error" message? Perhaps the proxy
has a timeout limit and the response exceeds that limit.
The startup="true" should cause a scan on server startup. John might
have more thoughts on what is going on here.
What messages do you get for this request in the threddsServlet.log
file? And is there a message for this request in your access logs?
Ethan
On 11/21/2011 9:59 AM, Rich Signell wrote:
> Bob,
>
> My FMRC featureCollection contains the line:
>
> <update startup="true" rescan="0 30 6 * * ? *" trigger="allow"/>
>
> and I thought the startup="true" meant that the metadata for the
> aggregation would be generated 1st on server startup, not when the
> first user stumbles on the aggregation.
>
> But I could be wrong, as I don't see any explicit mention of what
> "startup=true" means on the FeatureCollections page:
>
> http://www.unidata.ucar.edu/projects/THREDDS/tech/tds4.2/reference/collections/FeatureCollections.html
>
> In any case, I never got this message before:
> "Proxy Error: The proxy server received an invalid response from an
>>> upstream server.
>
> Do you think this is just triggered by the aggregation of metadata
> taking too long?
>
> Thanks,
> Rich
> On Mon, Nov 21, 2011 at 11:33 AM, Bob Simons <Bob.Simons@xxxxxxxx> wrote:
>> This may or may not explain the problem:
>>
>> My understanding is:
>> THREDDS uses what programmers call "lazy" instantiation, meaning that it
>> doesn't initialize datasets proactively, it waits until they are requested.
>> Similarly, if a dataset needs to be updated, THREDDS doesn't update it
>> until there is a request for the dataset.
>> Also, when a dataset is being initialized or updated, the old version of the
>> dataset is not available. For datasets with lots of files, (re)initializing
>> the dataset may take some time.
>>
>> So your initial request may be the initial request, which causes the dataset
>> to be initialized.
>>
>> On 11/21/2011 7:47 AM, Rich Signell wrote:
>>>
>>> Thredds Folk,
>>> I upgraded my server to Tomcat7/TDS4.2.9 and now I'm getting some
>>> problems with large aggregations (specifically, and FMRC with 1500
>>> files).
>>>
>>> When I restart tomcat and try to access the "best time series" dataset
>>> for the first time, I get:
>>>
>>> "Proxy Error: The proxy server received an invalid response from an
>>> upstream server.
>>> The proxy server could not handle the request GET
>>> /thredds/catalog/coawst_2_2/fmrc/catalog.html.
>>> Reason: Error reading from remote server"
>>>
>>> If I then try to access the best time series again, it works.
>>>
>>> I'm curious whether others are seeing this and what the problem is.
>>>
>>> In the featureCollectionScan.log, I see this:
>>>
>>> [2011-11-21T09:50:32.117-0500] INFO
>>> thredds.inventory.CollectionUpdater: Schedule startup scan for
>>> Config{name='coawst_2_2',
>>> spec='/usgs/vault0/coawst/coawst_2/Output/coawst_us_#yyyyMMdd_HH#.nc$',
>>> olderThan='10 min', recheckAfter='null'
>>> UpdateConfig{startup=true, rescan='0 30 6 * * ? *', triggerOk=true}
>>> ProtoConfig{choice=Penultimate, change='null', param='null',
>>> outerNcml='[Element:<netcdf [Namespace:
>>> http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2]/>]',
>>> cacheAll=true}
>>> FmrcConfig: regularize=false datasetTypes=[Best]} at Mon Nov 21
>>> 09:51:02 EST 2011
>>>
>>> Does that look okay?
>>>
>>> Thanks,
>>> Rich
>>
>> --
>> Sincerely,
>>
>> Bob Simons
>> IT Specialist
>> Environmental Research Division
>> NOAA Southwest Fisheries Science Center
>> 1352 Lighthouse Ave
>> Pacific Grove, CA 93950-2079
>> Phone: (831)658-3205
>> Fax: (831)648-8440
>> Email: bob.simons@xxxxxxxx
>>
>> The contents of this message are mine personally and
>> do not necessarily reflect any position of the
>> Government or the National Oceanic and Atmospheric
>> Administration.
>> <>< <>< <>< <>< <>< <>< <>< <>< <><
>>
>
>
>
--
Ethan Davis UCAR Unidata Program
edavis@xxxxxxxxxxxxxxxx http://www.unidata.ucar.edu
