Improve db4o linq query

I got a problem with this linq query:

from PersistedFileInfo fi in m_Database
from PersistedCommit commit in m_Database
where commit.FileIDs.Contains( fi.ID )
where fi.Path == <given path>
select new Commit( m_Storage, commit );

      

        
        
        
      

    

As you can see, each PersistedCommit

contains Collection<int>

, called FileIDs

, which connects it to its PersistedFileInfo

s. I want to select all previous commits of a specific fileInfo (which is identified by its path).

I have about 800 PersistedFileInfo

and 10 PersistedCommit

s. The request takes about 1.5 seconds - it's too long. The object's contractor Commit

only stores the two given arguments, so there is no timeloss here.

My question is:
Could this query be rewritten to perform better - or is it a db4o issue (use SODA query instead)?