How to solve <type 'exceptions.KeyError'> '\x00' error

[mostwanted]

There was a electrical power cut in my area today, it happened while i was working on my application. When the power returned & I tried to continue with my application I got this error:
"'<'type 'exceptions.KeyError'> '\x00'"
Now my application is NOT working! This is not the first time, i have had to start another project from scratch but i cant with this current one because alot has been done on it, i need to know what this error is!

Below is the stack trace to the error:

Traceback

Traceback (most recent call last):
File "C:\Users\.........\Documents\web2py\gluon\restricted.py", line 219, in restricted
exec(ccode, environment)
File "C:/Users/........../Documents/web2py/applications/Power_Vault/models/dbcurrentV.py", line 16, in <module>
Field('posted_by', 'reference auth_user', default=auth.user_id, readable=False, writable=False))
File "C:\Users\.......\Documents\web2py\gluon\packages\dal\pydal\base.py", line 590, in define_table
table = self.lazy_define_table(tablename, *fields, **kwargs)
File "C:\Users\.......\Documents\web2py\gluon\packages\dal\pydal\base.py", line 624, in lazy_define_table
polymodel=polymodel)
File "C:\Users\......\Documents\web2py\gluon\packages\dal\pydal\adapters\base.py", line 798, in create_table
return self.migrator.create_table(*args, **kwargs)
File "C:\Users\......\Documents\web2py\gluon\packages\dal\pydal\migrator.py", line 296, in create_table
sql_fields_old = pickle.load(tfile)
File "pickle.py", line 1378, in load
File "pickle.py", line 858, in load
KeyError: '\x00'

If anyone out there knows what this is I could really use your help in resolving it, i am desperate . Thank you!

[Val K]

It seems that dal-metafiles are broken. Did you try to fix it as the book suggests?

[mostwanted]

Please refer me, what page, I will be lying if i said i looked it up!

[Val K]

Chapter 6 Fixing broken migrations

[mostwanted]

Thanks for that reference Val K, i'm going through it trying to figure out my problem, every problem that is stated in the book that could cause broken migrations involves bad programming habits, thats by understanding anyway, like defining a field as one type and redefining it into another type meanwhile saving information in it. The other involves partial committing of complex transaction. I haven't encountered any of these so i'm still trying to figure out where my error falls & how I can apply the given solutions.

Mostwanted

On Saturday, December 1, 2018 at 11:39:18 AM UTC+2, Val K wrote:

Chapter 6    Fixing broken migrations

[Leonel Câmara]

You can probably fix this simply by doing a fake migration to rebuild the .table files. Run your app with migrate=True and fake_migrate=True in your DAL.

[mostwanted]

What concerns me is that I developed a standalone application with web2py & every-time there is a sudden power cut which is an issue in my area, when switching on a computer to continue using the application we find that the application has crushed! Isn't there a away to avoid the application crushing every-time there is a power cut?!

[Leonel Câmara]

The application should be running with migration disabled in production in which case this won't happen.

[mostwanted]

Can you please explain further Leonel?

[Jon Subscripted]

Hi Leonel,

Could a PC reboot lead to the same problem Mostwanted reported?

Regards, Jon.

Libre de virus. www.avast.com

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[Leonel Câmara]

Jonsubs yes it could if for some reason web2py wasn't graciously stopped which can happen depending on the OS and if web2py is taking too long to shutdown. Again don't leave migrations enabled otherwise the pickle files will be being written which if stopped halfway can lead to corrupted pickle files.

[Jon Subscripted]

Thanks!

On Tue, Jan 15, 2019 at 12:36 PM Leonel Câmara <leonel...@gmail.com> wrote:

Jonsubs yes it could if for some reason web2py wasn't graciously stopped which can happen depending on the OS and if web2py is taking too long to shutdown. Again don't leave migrations enabled otherwise the pickle files will be being written which if stopped halfway can lead to corrupted pickle files.

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