[webservices] continuous data

Bruce Weertman bruce at iris.washington.edu
Tue Dec 20 09:14:30 PST 2011


John:

A day is probably a good choice for a "block" size. 

Also, take a look at the bottom of this web page:

http://www.iris.edu/ws/doc/bulkdataselect_help.htm

As Rich pointed out, our file organization is all data from one station for one day into one file.
The code that pulls the data out of one of the files works more efficiently if you ask for all of the information
that you want for that one station-day at once, rather than in a bunch of requests. 

So if you were say getting all BHZ, BH1, BH2 for a network, you would want to
request station by station rather than channel by channel

ie
one request
IU ANMO 00 BHZ time-range
IU ANMO 00 BH1 time-range
IU ANMO 00 BH2 time-range

then next station request
etc
...

but not
IU ANMO 00 BHZ time-range
IU QSPA 00 BHZ time-range
IU ADK 00 BHZ time-range
etc
...
then the next channel request

-Bruce

On Dec 20, 2011, at 10:41 AM, Rich Karstens wrote:

> Hi John,
> 
> The data in our archive is generally stored in files comprised of all the channels of a station for a specific day.   Thus, there are advantages to requesting 'blocks' of exactly one day.  Another advantageous technique would be to request all channels for a particular station in  the same request.  All of this pretty much comes down to disk I/O, file seeks and parsing.
> 
> I'm sure we'd love to see any throughput numbers you come up with.
> 
> Hope that helps,
> 
> Rich
> 
> 
> John D. West wrote:
>> Hi.
>> 
>> If I want to request continuous data via the web services, is there an optimal block size (i.e., ~1 day) to request at a time?
>> 
>> I overheard a bit of conversation on this at AGU, but didn't get the complete story.
>> 
>> Thanks!
>> 
>>     -- John
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