Hi, I see the new catalog stuff makes use of new BTrees. I presume the big advantages the new catalog has are from these new BTrees. I know of a few products which also use these BTrees (Squishdot and some internal ones here spring to mind) so I guess they should be upgraded too? Well, I had a look at the _convertBTrees method in Catalog.py and it all made sense, so I'm guessing the folowing would be the correct way to convert some BTrees? from BTrees import IOBTree, BTree, convert myBTree if type(myBTree is not IOBTree): mynewBTree = IOBTree() convert(myBTree,mynewBTree, 200) ...or.. if type(myBTree is not BTree): mynewBTree = BTree() convert(myBTree,mynewBTree, 200) I'm guessing the 200 is how many items get put in each bucket? What should influence the choice of this number? cheers, Chris