[Python-bugs-list] [ python-Bugs-727137 ] use bsddb185 if necessary in dbhash

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Bugs item #727137, was opened at 2003-04-24 21:56
Message generated for change (Comment added) made by loewis
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Category: Python Library
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Skip Montanaro (montanaro)
Assigned to: Barry A. Warsaw (bwarsaw)
Summary: use bsddb185 if necessary in dbhash

Initial Comment:
I've had this patch sitting around for awhile.  I think if the new
bsddb stuff can't be built and the user enables the bsddb185
module in Modules/Setup that dbhash should also try that
module when setting things up.

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>Comment By: Martin v. Löwis (loewis)
Date: 2003-05-03 23:20

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I agree that people will want to use bsddb185 to open
existing files, and we should make this readily available.
At the same, we should not  provide easy means to create new
files.

So I suggest to reject this patch: If anything is done about
dbhash, it should check, on open, what version of the
database library needs to be used to open an existing file.

It is indeed the case that the current whichdb
implementation is not capable of distinguishing BSDB on-disk
format versions. Such version information is available
inside the file, and it would be possible to teach whichdb
about that.

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Comment By: Skip Montanaro (montanaro)
Date: 2003-05-03 22:17

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There are valid reasons why people don't update their db library.  The
most obvious one that occurs to me is that the system itself stores
files with that version of the library which applications need to read
(I remember the pwd module had this problem at one time.  Probably
still does under the correct circumstances.)

As for whichdb returning "bsddb185", that can only happen if we
are willing to an "open" method to it.  Even then, whichdb will
probably have to be made more discriminating (distinguishing
files readable via db 1.85 ("bsddb185") and files readable by
more recent versions ("dbhash").


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Comment By: Martin v. Löwis (loewis)
Date: 2003-05-03 17:18

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-1. I think users should make an explicit decision to use
bsddb 1.85, and should get an error if they use any of the
libraries on top of it.

The only reasonable exception might be whichdb, which could
say 'bsddb185', if it recognizes the file format.

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