shelve.py and "Invalid argument" error when try a "sync"

[Steve Kirsch]

I have a little application that writes a very small amount of data
every couple of days to a file. It's been running almost 1 month with
no problem.... the file stays open, and i just sync to write out my
changes. Now, all of a sudden, i start seeing this error from the
.sync() method in shelve.py.

I am running on windows. My database is only 2K in size (there are
only about 12 keys in the entire database). And I used the
shelve.open(...) to create the file.

The error message looks like this:

  File "database.py", line 253, in save
    self.dict.sync()
  File "c:\Python22\lib\shelve.py", line 94, in sync
    self.dict.sync()
error: (22, 'Invalid argument')

So I've seen others report this as well...I'm just adding my own
experience.

I'm now going to re-write it so i close the file and re-open all the
time and see if that works around the problem.