TypeError: 'NoneType' object has no attribute '__getitem__' while opening backupdb

[daira]

$ tahoe --version
allmydata-tahoe: 1.10.0
foolscap: 0.6.4
pycryptopp: 0.6.0.1206569328141510525648634803928199668821045408958
zfec: 1.4.5
Twisted: 13.2.0
Nevow: 0.10.0
zope.interface: unknown
python: 2.7.7
platform: Linux-debian_jessie/sid-i686-32bit_ELF
pyOpenSSL: 0.13.1
simplejson: 3.5.2
pycrypto: 2.6.1
pyasn1: 0.1.7
mock: 1.0.1
setuptools: 3.6


$ tahoe backup ~ LAE:backups
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/allmydata/scripts/runner.py", line 156, in run
    rc = runner(sys.argv[1:], install_node_control=install_node_control)
  File "/usr/lib/python2.7/dist-packages/allmydata/scripts/runner.py", line 141, in runner
    rc = cli.dispatch[command](so)
  File "/usr/lib/python2.7/dist-packages/allmydata/scripts/cli.py", line 574, in backup
    rc = tahoe_backup.backup(options)
  File "/usr/lib/python2.7/dist-packages/allmydata/scripts/tahoe_backup.py", line 325, in backup
    return bu.run()
  File "/usr/lib/python2.7/dist-packages/allmydata/scripts/tahoe_backup.py", line 90, in run
    self.backupdb = backupdb.get_backupdb(bdbfile, stderr)
  File "/usr/lib/python2.7/dist-packages/allmydata/scripts/backupdb.py", line 84, in get_backupdb
    version = c.fetchone()[0]
TypeError: 'NoneType' object has no attribute '__getitem__'

[zwick]

The original backupdb.sqlite file that was created

[zooko]

Line 84​ is merely reading the *version* of the backupdb, so this particular one must have been corrupted. I haven't looked at it yet.

zwick: what happens when you rm it (or mv it aside) and then try again?

[zwick]

Replying to zooko:

Line 84​ is merely reading the version of the backupdb, so this particular one must have been corrupted. I haven't looked at it yet.

zwick: what happens when you rm it (or mv it aside) and then try again?

mv'ing (moving it aside by renaming it to backupdb.sqlite.BACKUP) and then running the "tahoe backup" command again worked correctly.

[daira]

Can you think of anything that might have caused the original file to be corrupted -- was a previous tahoe backup interrupted, for example?

[zwick]

Replying to daira:

Can you think of anything that might have caused the original file to be corrupted -- was a previous tahoe backup interrupted, for example?

I cannot recall anything that happened prior to this. I did a clean install of tahoe-lafs and was following the steps at: ​https://leastauthority.com/howtoconfigure. I am going to do a clean install on a different machine running the same versions of everything (except it will be 64bit instead of 32bit) and see if the same thing happens.

[zwick]

Replying to zwick:

Replying to daira:

Can you think of anything that might have caused the original file to be corrupted -- was a previous tahoe backup interrupted, for example?

I cannot recall anything that happened prior to this. I did a clean install of tahoe-lafs and was following the steps at: ​https://leastauthority.com/howtoconfigure. I am going to do a clean install on a different machine running the same versions of everything (except it will be 64bit instead of 32bit) and see if the same thing happens.

On a different machine, I did a clean install of tahoe-lafs,followed the steps at the URL above, and everything worked correctly. The only difference between these two machines is that the one that had the error uses a 32bit kernel/userspace and the later (that ran without issues) uses a 64bit kernel/userspace.

[zooko]

This happened again, with AB:

Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/allmydata/scripts/runner.py", line 156, in run
    rc = runner(sys.argv[1:], install_node_control=install_node_control)
  File "/usr/lib64/python2.7/site-packages/allmydata/scripts/runner.py", line 141, in runner
    rc = cli.dispatch[command](so)
  File "/usr/lib64/python2.7/site-packages/allmydata/scripts/cli.py", line 574, in backup
    rc = tahoe_backup.backup(options)
  File "/usr/lib64/python2.7/site-packages/allmydata/scripts/tahoe_backup.py", line 325, in backup
    return bu.run()
  File "/usr/lib64/python2.7/site-packages/allmydata/scripts/tahoe_backup.py", line 90, in run
    self.backupdb = backupdb.get_backupdb(bdbfile, stderr)
  File "/usr/lib64/python2.7/site-packages/allmydata/scripts/backupdb.py", line 84, in get_backupdb
    version = c.fetchone()[0]
TypeError: 'NoneType' object has no attribute '__getitem__'

What should we do if the backupdb file is corrupted? Delete it and proceed? Or stop with a useful error message?