This message:

NOTICE:  Message from PostgreSQL backend:
        The Postmaster has informed me that some other backend
        died abnormally and possibly corrupted shared memory.
        I have rolled back the current transaction and am
        going to terminate your database system connection and exit.
        Please reconnect to the database system and repeat your query.
server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
connection to server was lost

I get more or less frequently.

what to do?

regards fredrik chabot