This is for people using dtuple.py; a dtuple.DatabaseTuple instance
keeps a reference to cursor.description, which is not picklable because
psycopg2 doesn't export the Column namedtuple it uses.
This commit exports the Column namedtuple, and includes a test to verify
the pickle/unpickle works after exporting Column.
It is raised on 32 bits by PyArg_ParseTuple. We may work around on
truncate (maybe parsing a py_ssize_t) but we would have the same problem
on seek as the offset is signed.
If psycopg supports lo64 but the server doesn't the user may pass values
that would overflow the api range, resulting in:
lo.seek((2<<30))
*** OperationalError: ERROR: invalid seek offset: -2147483648
Also improved the error messages and guard against INT_MIN for negative
seek offsets.
Correction to type adaption example
It is OK for an adapted object to return the escaped string on
__str__ calls but getquoted() is the canonical method.
`close()` is implicitly called by `__exit__()`, so an exit on error
would run a query on a inerr connection, causing another exception
hiding the original one. The fix is on `close()`, not on `__exit__()`,
because the semantic of the latter is simply to call the former.
Closes#262.
Deallocating closed large objects failed to decrement the connection
refcount. The fact the lobject is closed doesn't matter for refcount.
Issue detected by the always useful scripts/refcounter.py
With an extra bit of unrequested whitespace love.
This makes possible to import _psycopg directly, after adding the
package directory to the pythonpath. This enables hacks such as:
sys.path.insert(0, '/path/to/psycopg2')
import _psycopg
sys.modules['psycopg2._psycopg'] = _psycopg
sys.path.pop(0)
which can work around e.g. the problem of #201, freeze that cannot
freeze psycopg2. Well, freeze cannot freeze it because it's just not
designed to deal with C extensions. At least now the frozen application
can hack the pythonpath and work around the limitation by importing
_psycopg as above and then doing the rest of the imports normally.
Keeping long-lived references to python objects is bad anyway: the
tz module couldn't be reloaded before.
