zombie connections

Hi,

Suppose that the server is executing a lengthy query, and the client
breaks the connection. The operating system will be aware that the
connection is no more, but PostgreSQL doesn't notice, because it's not
try to read from or write to the socket. It's not paying attention to
the socket at all. In theory, the query could be one that runs for a
million years and continue to chew up CPU and I/O, or at the very
least a connection slot, essentially forever. That's sad.

I don't have a terribly specific idea about how to improve this, but
is there some way that we could, at least periodically, check the
socket to see whether it's dead? Noticing the demise of the client
after a configurable interval (maybe 60s by default?) would be
infinitely better than never.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company