a psycopg user is reporting [1] that the library is not marking the connection as closed and/or bad after certain errors, such as a connection timeout. He is emulating the error by closing the connection fd (I don't know if the two conditions result in the same effect, but I'll stick to this hypothesis for now).
Testing with a short C program [2] it seems that indeed, after closing the fd and causing an error in `PQconsumeInput`, the connection is deemed in good state by `PQstatus`. A similar test gives the same result after `PQexec` is attempted on a connection whose fd is closed (tests performed with PostgreSQL 9.3.5).
Is this intentional? Is there a better way to check for a broken connection?
BTW, PQsocket() returns -1 after PQfinish().
If we mark the connection as closed every time `PQconsumeInput` returns 0 (or `PQexec` returns null, which are the two code paths affecting psycopg) would it be too aggressive and cause false positives?