No, you cannot append to a file on the dfs and your app should be able to treat multiple files as one single logical file (as you point out). But in your case, it seems like you could design your app to have some buffering, for example, you could have a buffer for the n different files, and could flush the buffer as different files to the dfs only when you have reached a certain limit on the amount of data in the buffer. I am not sure whether fault handling is of concern to you but there is the danger of losing the buffered messages if your app goes down. One way to handle this - assuming you have the ability to reprocess messages, you could checkpoint the state of the message processor in the dfs - the state could include the last message ID you flushed, and the next time your app starts up, read the checkpoint file from the dfs, get the ID, and process messages starting from (ID + 1).
-----Original Message----- From: Open Study [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 26, 2007 8:42 PM To: [email protected] Subject: is that possible to make MapFile "mutable" ? Hi all, MapFile doesn't support append mode of creation, so every time the existing mapfile would be overwritten if a new one with same name is created. Is there anyway I can append to an MapFile or alike without erasing the old content? or it doesn't makes sense at all? In my scenario I need to split mass (count by tens of millions) messages according to certain rules and put them into different mapfiles, which are supposed to get updated when new messages come in. Since I didn't find a way to make mapfile appendable, I have to create new mapfiles, so one mapfile can contain as little as one message in worst case and I will have to later merge them with their proper siblings. Regards
