I am attempting to get information on the pg_subtrans directory. I found this morning that one had a large number of files queued in it. It filled the disk partition on which pgdata resides. After moving, linking and restarting as a temporary solution, the engine properly worked off these files. So, I'm trying now to get to the root cause of why it filled in the first place -- however I'm not sure when postgres engine uses this directory. I've searched the documentation and mailing list archive, but can't find much. Can anyone give me a link or some more information?