Since now I don't need the transaction summary any more (just number of records associated with the transaction at the currentFile), I will need to use temporary files, and rename them as you suggested. - I will open a journal file with a temporary name. (Open here, means gets it from the cached files, or create a new one). - As I read the journal files I add the valid records to the temporary file. (I will off course open new files as I fill the file). - Add a temporary small file when I start renaming the files, and deleting the old files. and delete that file when I'm done. The only issue I have now is allowing concurrent appends to the journal, as I'm compacting the files. The problem is, when deleteing or updating a record, I don't know where the AddRecord is going to be located at. So, I don't know where to add the negative value to. So, what I'm thinking as a solution is: - During compacting, all Adds, updates and deletes are stored to the current-file, as we aways do. - But instead of discounting POSFiles right away, I cache those IDs on a collection. When I'm done compacting I do a fast operation applying the reference counts accordingly. - Case the server is interrupted during reload, the delete or update will take the original location of the record. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4239872#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...