IExtObjectContainer.GetByID in version 6.4 is supposed to throw InvalidIDException (the documentation states that it returns nell, but I never get that value).

I found that with some ID OutOfMemoryException is called and the database is closed. The values of ID that get this behavoiur seems to vary somehow from db to db, but I found that

IObjectContainer oc1 = Db4oFactory.OpenFile("database.yap");

OutOfMemoryException ex1 = null;

for (long i = 1; i < 100; i++)

{

try

{

object obj = oc1.Ext().GetByID(i);

}

catch (Db4objects.Db4o.Ext.InvalidIDException ex)

{

}

catch (OutOfMemoryException ex)

{

ex1 = ex;

break;

}

}

exits with the databse closed on i = 17 on all my test databases.
 
 
 I have done some tracing in the code to find the source of the problem. It seems there's something unexpected in the file structure. LocalObjectContainer.ReadReaderOrWriterByID calls LocalTransaction.GetCurrentSlotOfID to get the right slot.

ReadPointer seems to find something unexpected. It seems not to recognize that the address is invalid. If the length is reasonable the error is catched in ReadEncrypt as an IncompatibleFileSystem exception, but il the length is big there is an OutOfMemory and the database is closed.

I suspected the problem was that I used databases generated with 6.1, but I get the same result with newly generated databases, even without any deleted item.