[ZODB-Dev] new user questions

[Jim Fulton]

On Nov 25, 2008, at 3:28 PM, richrad miller wrote:

> Two questions from a new user
>
> I am running UBUNTU 8.04
>
> 1. If I open a zodb file and (Ctrl)c the process, I receive the
> following message on trying to reopen the file.  Is there a way to
> recover ?
>
> Traceback (most recent call last):
>  File "show_rate.py", line 298, in <module>
>    zdb = zodbmod.WorkZodb('/work/tmp/zdb/rates.fs','old')
>  File "/work/python/modules/zodbmod.py", line 12, in __init__
>    self.storage = FileStorage.FileStorage(self.path)
>  File
> "/usr/lib/python2.5/site-packages/ZODB3-3.8.1b7-py2.5-linux-i686.egg/ 
> ZODB/FileStorage/FileStorage.py", line 115, in __init__
>    self._lock_file = LockFile(file_name + '.lock')
>  File
> "/usr/lib/python2.5/site-packages/ZODB3-3.8.1b7-py2.5-linux-i686.egg/ 
> ZODB/lock_file.py", line 86, in __init__
>    raise
>  File
> "/usr/lib/python2.5/site-packages/ZODB3-3.8.1b7-py2.5-linux-i686.egg/ 
> ZODB/lock_file.py", line 80, in __init__
>    _lock_file(fp)
>  File
> "/usr/lib/python2.5/site-packages/ZODB3-3.8.1b7-py2.5-linux-i686.egg/ 
> ZODB/lock_file.py", line 59, in _lock_file
>    raise LockError("Couldn't lock %r" % file.name)
> LockError: Couldn't lock '/work/tmp/zdb/rates.fs.lock'

Normally, exiting the process will free the lock.  As someone else  
suggested, you can try removing the lock file.
As Andreas pointed out, it is usually a good idea to use ZEO so you  
can have multiple application processes
share a single database.

> 2.  Is there a way to open a zodb file in "read only" mode.


It depends on the storage, but both FileStorage and ZEO support a  
read_only option.  In the case of a file storage, opening it read-only  
doesn't require acquiring the lock.

Jim

--
Jim Fulton
Zope Corporation