[thredds] Detaails as to how recheckEvery works, and optimizing access to large aggregate datasets

[Roy Mendelssohn]

Hi:

We are working with someone who is implementing a TDS for a large  
aggregated dataset, in this case output from ROMS models.  The  
specific questions asked were:

> Will recheckEvery also check existing files to see if they have  
> changed (had records added)? I only ask because, as I mentioned, we  
> are considering adding the hourly files to the current month's  
> file. Therefore, the current month's file will change (have a new  
> record) every hour.
>
> Also, when the aggregation finds a new file (or modified one if it  
> checks that) will the dataset need to be retouched to speed load  
> times?
>

but the underlying question is also how best to set up the  
aggregation, is it still true that things are speeded up if on  
startup you "touch" each "file" so that the coordinate info is read  
into cache, and exactly what does get checked and how on recheckEvery.

Thanks for any help,

-Roy
.



**********************
"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."