Marco,
You have a few options for doing what you describe, but you will have to
balance the trade-offs for what you choose. The short answer to your
last question is "no" - we cannot dynamically update - because the
operating system does not send a notification to the TDS when a
directory changes under Java 6. Version 5 of the TDS will use features
of Java 7 that enable operating system notifications, at which point we
have a plan for "dynamic" updating. Without any sort of notification
from the o/s, we must poll a directory to find out if it has changed.
If not too much is going on with your filesystem, then the o/s will
probably cache the information and be able to respond quickly, though if
your filesystem is very busy, then there is no reasonable expectation
that the directory information will be cached. Thus, you must scan
repeatedly to find out if a new file has shown up.
The other option for you, perhaps better, is to set up a feature
collection instead of an NcML aggregation. If you have information
about how or when the new files are delivered, you can specify an update
element with a cron expression or set up an external trigger to update
your collection without lots of extra overhead. Details are here:
http://www.unidata.ucar.edu/projects/THREDDS/tech/tds4.3/reference/collections/FeatureCollections.html
http://www.unidata.ucar.edu/projects/THREDDS/tech/tds4.3/tutorial/FeatureCollectionsTutorial.html
-Lansing
On 4/4/2013 10:19 AM, MNETO (simepar) wrote:
Helo Lansing,
The frequency of my data is 10 minutes. I would like to update
whenever new data is available. It does not seem efficient refresh
every 4 seconds due to the large amount of data that has to be read
from the directory. Unless the ncML read only the new files added to
the directory.
Then! Can not dynamically update?
Thanks for your help!
*|||| ||||||||||**|**||| Marco Aurélio Silva Neto*
*|||| *IIIIIIIII*||**||| *Analista de Sistemas
*||||||||||||| ||||| **Fone*: (41) 3320-2000 - Ramal: 2079
*
*
2013/4/4 Lansing Madry <madry@xxxxxxxxxxxxxxxx
<mailto:madry@xxxxxxxxxxxxxxxx>>
Good Morning Marco,
You can set the value of recheckEvery to units of seconds. For
instance:
recheckEvery="4 sec"
Regards,
Lansing Madry
Unidata
Boulder, Colorado
On 4/4/2013 8:15 AM, MNETO (simepar) wrote:
Good Morning,
I use ncML. Follows a ncML configuration file (PPI_DZ_0.ncml)
to one data type. Although in my ncML file has the field
"recheckEvery="1 min"", I need update my data always when a new
data is avaliable. I don't can to wait the time of one minute for
update.
<netcdf
xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
<aggregation dimName="time" type="joinNew" recheckEvery="1 min">
<variableAgg name="PPI_DZ_0"/>
<scan location="./" suffix=".nc"
dateFormatMark="RAD#yyMMddHHmmss"/>
</aggregation>
</netcdf>
Is there any way to force update from the command line or
configuration in file ncML?
Thanks
*|||| ||||||||||**|**||| Marco Aurélio Silva Neto*
*|||| *IIIIIIIII*||**||| *Analista de Sistemas
*||||||||||||| ||||| **Fone*: (41) 3320-2000
<tel:%2841%29%203320-2000> - Ramal: 2079
*
*
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