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Sat Apr 21 12:02:16 EDT 2001 · http://mail.python.org/pipermail/python-list/2001-April/095479.html

Ok, no reply....guess I didn't capture anyones interest, doh! Can anyone at
least point me in the right direction for more information on the shelve
module and what the hell might be causing a "bsddb.error: (0, 'Error')".

Dont make me beg, I am pitiful enough as is ;)

Blobby

Mark blobby Robinson wrote:

> Hi,
>
> I wonder if anyone can provide some insight to an error I am getting. I
> am
> unable to figure out what is causing it. I am a developing some software
>
> for a bioinformatics research lab, specifically for the analysis of DNA
> sequences.
>
> Firstly, I am using python 1.5.2 on a machine running red hat linux 7.0.
>
> The machine is running at 700Mhz with 380Mb RAM and about 1GB free space
>
> on root.
>
> In the broadest terms the program is generating a list of "motif"
> objects and when the length of this list exceeds one million I am
> shelving the objects. The error that I am getting is that while I am
> shelving the objects I sometimes receive the following exception
> bsddb.error:
>
> 90% Written
> 100% Written
> Traceback (innermost last):
>   File "runMotif.py", line 34, in ?
>     filename = genMotifs(posList, S, filename)
>   File "motif.py", line 161, in genMotifs
>     motifs = writeMotifs(motiflist, filename, S)
>   File "motif.py", line 189, in writeMotifs
>     motifDict[hstring] = motif(x, S)
>   File "/usr/lib/python1.5/shelve.py", line 71, in __setitem__
>     self.dict[key] = f.getvalue()
> bsddb.error: (0, 'Error')
>
> Ok, now I'll be a bit more specific about what I am doing at the
> shelving step! Each of the  "motif" objects in the list contains 3
> attributes which contain strings of length 5 to 10. I use these strings
> to generate a unique key for each motif in the shelved data file. Then
> for each object in the list I perform a check to see if that key has
> been generated previously. If key is not found in shelved file then
> I add the object, else I simply update the shelved object accordingly.
> The code is as follows:
>
> def writeMotifs(motiflist, filename, S):
>      motifDict = shelve.open(filename)
>      print "writing to %s" % filename
>      count = 0
>      for x in motiflist:
>           hstring = x[0][0] + '_' + x[1][0] + '_' + x[2][0]
>           if count % 100000 == 0:
>                print "%s%% Written" % (count/10000)
>           if motifDict.has_key(hstring):
>                temp = motifDict[hstring]
>                if checkNoMotifOverlap(temp, x) is not 1:
>                     temp.setCount()
>                     temp.setPos(x)
>                     motifDict[hstring] = temp
>               else:
>                    motifDict[hstring] = motif(x, S)
>               count = count + 1
>      length = len(motifDict)
>      motifDict.close
>  return length
>
> This program is taking a huge combinatorial problem and is therefore
> producing absolutely piles of data. I have checked to ensure that I am
> not running out of RAM during execution, and although the shelved data
> file is getting pretty big I have so far only used run the analysis on
> short sequences producing output in the region of 90-160MB size. The
> fact that it falls over at different sizes suggests to me that I am not
> hitting some linux defined constant for file sizes or the like, but
> I can't think what it could be. I have check the number of objects in
> the shelved file and it has ranged between 90,000 and 143, 000 before it
>
> keels over and dies.
>
> Can anyone suggest any reason this problem might be occuring?
>
> cheers
>
> Blobby

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bsddb.error