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 Post subject: NGRB2PCG32 Bug Report
PostPosted: Fri Jun 23, 2006 4:44 pm 
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Joined: Fri Jun 25, 2004 11:42 pm
Posts: 298
All,

This is to announce a bug in NGRB2PCG32 which you may encounter. It seems the GRIB II decompression routine within NGRB2PCG32 has what is called a 'memory leak' which means for every GRIB II message it has to decompress, the utility leave behind memory it does not release and when the next message comes along, the utility requests a new block of memory. Eventually, depending on how large the data set is, NGRb2PCG32 will use up all of your systems memory and die. This usually does not occur until it has processed over 1.3 GB of data but the potential is still there.

I am working on correcting it but for the time being, you may have to work with a reduced data set. NGRB2PCG32 works fine with GRIB I or uncompressed GRIB II files.

Thanks for your patience with this problem,
Jeff Krob
PCGRIDDS32/WINGRIDDS System Developer


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 Post subject: Status of this fix
PostPosted: Sat Oct 28, 2006 7:38 pm 
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Joined: Sat Aug 07, 2004 12:57 am
Posts: 128
Location: North Carolina
Jeff,

Just wondering what the status of the fix for this issue is. Since data on the NOMADS servers has been turned off again or for some other reason it is not available, I have been trying to work with grib2 files. I like the grib2 files because they are compressed and thus the file sizes are smaller which in turn makes for faster download times. However, because of the issue you have posted here I am having trouble being able to work with these files. Hope a fix is in the work soon before NWS does away with the grib1 files.

Thank you,

Kevin


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 Post subject:
PostPosted: Sat Oct 28, 2006 8:46 pm 
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Joined: Sat Aug 07, 2004 12:57 am
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Location: North Carolina
Jeff,

After further working with grib2 files I think there may be a problem with the files on the NWS servers. Some files just won't finish converting when being run throught NGRB2PCG32. The program will be running just fine and then just quit.

http://www.bellsouthpwp.net/n/c/nckev/WINGRIDDS/grib2_NGRB2PCG32-out.txt

This is just a part of the NGRB2PCG32.out file. At the bottom is where the program quit running. But I think it's a problem with the file and not NGRB2PCG32 and here is why I think that. I logged out after it bombed out and logged back in to clear any memory leak and ran that forecast hour (in this case the 60 hour forecast) and it did again. It just stopped as you see in the data from the NGRB2PCG32.out file. If it is not the files on the NWS servers then there is a problem somewhere else.

Regards,

Kevin


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 Post subject:
PostPosted: Sun Oct 29, 2006 12:24 am 
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Joined: Fri Jun 25, 2004 11:42 pm
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Kevin,

Thanks for the additional info. (I really do need to remember to take out that additional debug info)...

Well.......this is a new one on me. I too think it is a data file problem. NGRB2PCG32 treats every GRIB message (a message is a data packet for every GRIB parameter so HGHT 500 is a separate message from HGHT 850 & every GRIB file is amde up of numerous GRIB messages) as a separate processing event so it will either work with every GRIB message or it won't work with any (aside from the memory leak problem).

As far as finding the problem, I'm gong to release the next Beta version of WINGRIDDS around Nov. 1st & (hopefully) the final release Dec. 1. I have found a different version of GRIB2 processing code & I'm going to try to replace to code which is already there but that will take some work & time.

It *is* processing data...just not a large volume.

Thank you for you patience,
Jeff


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 Post subject:
PostPosted: Wed Nov 01, 2006 12:11 am 
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Kevin,

the fix is on it's way...

Jeff


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 Post subject:
PostPosted: Wed Nov 01, 2006 2:11 am 
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Joined: Sat Aug 07, 2004 12:57 am
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Location: North Carolina
Jeff,

Thank you sir. You da man!

Kevin


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