[spambayes-dev] db_* binaries for Windows, DB_RECOVER

[Skip Montanaro]

Dave Segleau at Sleepycat confirmed for me that making Windows binaries of
the Sleepycat db_* utilities available from the SpamBayes website would be
okay.  Who can take the time to make them available?  We would need to make
sure that db_recover will actually fix Mark Tabash's (and others?) database
file.

He also said that running db_recover isn't the correct solution.  The
correct way to do this is to create an environment object with the
DB_RECOVER flag set.  That's not compatible with the anydbm interface
however.  I see a few possible solutions:

    * Special case the situation where whichdb.whichdb() returns "dbhash"
      and make direct calls to the relevant bsddb package functions to
      create a db object which is resilient in a multi-threaded
      environment.  This might be done either using Python's lock facilities
      or using Sleepycat's environment locks.

    * Modify the behavior of bsddb.hashopen() (and cousins) so that it
      creates a DBEnv object with the DB_RECOVER flag and passes it to the
      DB() constructor:

          def hashopen(....):
              flags = bsddb._checkflag(flag)
              d = bsddb.db.DB(bsddb.db.DBEnv(bsddb.db.DB_RECOVER))
              ...

          bsddb.hashopen = hashopen

    * Provide locks around all database file accesses.

Skip