[ZODB-Dev] RelStorage: Unable to acquire commit lock

[Shane Hathaway]

Stefan H. Holek wrote:
> I try to use two relstorages, roughly following Evan's ZopeLabs recipe  
> [1]. This is how my zope.conf looks like:
> 
> [...]
> 
> However, when I want to mount the /sessions_folder I get this:
> 
> 2008-05-08 21:13:15 ERROR Zope.SiteErrorLog http://localhost:8080/manage_addProduct/ZODBMountPoint/manage_addMounts
> Traceback (innermost last):
>    Module ZPublisher.Publish, line 125, in publish
>    Module Zope2.App.startup, line 238, in commit
>    Module transaction._manager, line 96, in commit
>    Module transaction._transaction, line 395, in commit
>    Module transaction._transaction, line 498, in _commitResources
>    Module ZODB.Connection, line 730, in tpc_vote
>    Module relstorage.relstorage, line 529, in tpc_vote
>    Module relstorage.relstorage, line 513, in _vote
>    Module relstorage.relstorage, line 420, in _prepare_tid
>    Module relstorage.adapters.mysql, line 406, in start_commit
> StorageError: Unable to acquire commit lock

It takes a few moments for that error to appear, doesn't it?

Perhaps the scope of the commit lock in MySQL is the entire database 
server rather than just the database, which would explain this.  We 
should make sure each database has its own commit lock and pack lock.

Shane