urgent request : PSQLException: FATAL: could not open relation XXX: No such file or directory

 Hi

I am working on an application where Postgresql is used as the db. I have a trigger and three functions running on that trigger. The data in db is updated by a thread each 1 minute continuously.

I kept my application running for 2 days and on runtime Postgres stopped running. But when I restarted it and restarted my application I got the error “PSQLException: FATAL: could not open relation XXX: No such file or directory” . I found that some of the files in the db(data folder) are lost(just dissappeared). Can u explain me why it happened and how can I fix this problem, since this is blocking my application.