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3
NEWS
3
NEWS
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@ -5,6 +5,9 @@ What's new in psycopg 2.6.2
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^^^^^^^^^^^^^^^^^^^^^^^^^^^
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- Report the server response status on errors (such as :ticket:`#281`).
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- The `~psycopg2.extras.wait_select` callback allows interrupting a
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long-running query in an interactive shell using :kbd:`Ctrl-C`
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(:ticket:`#333`).
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- Raise `!NotSupportedError` on unhandled server response status
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(:ticket:`#352`).
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- Fixed `!PersistentConnectionPool` on Python 3 (:ticket:`#348`).
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@ -611,3 +611,6 @@ Coroutine support
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.. autofunction:: wait_select(conn)
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.. versionchanged:: 2.6.2
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allow to cancel a query using :kbd:`Ctrl-C`, see
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:ref:`the FAQ <faq-interrupt-query>` for an example.
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@ -223,6 +223,37 @@ What are the advantages or disadvantages of using named cursors?
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little memory on the client and to skip or discard parts of the result set.
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.. _faq-interrupt-query:
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.. cssclass:: faq
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How do I interrupt a long-running query in an interactive shell?
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Normally the interactive shell becomes unresponsive to :kbd:`Ctrl-C` when
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running a query. Using a connection in green mode allows Python to
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receive and handle the interrupt, although it may leave the connection
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broken, if the async callback doesn't handle the `!KeyboardInterrupt`
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correctly.
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Starting from psycopg 2.6.2, the `~psycopg2.extras.wait_select` callback
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can handle a :kbd:`Ctrl-C` correctly. For previous versions, you can use
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`this implementation`__.
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.. __: http://initd.org/psycopg/articles/2014/07/20/cancelling-postgresql-statements-python/
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.. code-block:: pycon
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>>> psycopg2.extensions.set_wait_callback(psycopg2.extensions.wait_select)
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>>> cnn = psycopg2.connect('')
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>>> cur = cnn.cursor()
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>>> cur.execute("select pg_sleep(10)")
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^C
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Traceback (most recent call last):
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File "<stdin>", line 1, in <module>
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QueryCanceledError: canceling statement due to user request
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>>> cnn.rollback()
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>>> # You can use the connection and cursor again from here
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.. _faq-compile:
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Problems compiling and deploying psycopg2
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@ -575,15 +575,20 @@ def wait_select(conn):
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from psycopg2.extensions import POLL_OK, POLL_READ, POLL_WRITE
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while 1:
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state = conn.poll()
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if state == POLL_OK:
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break
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elif state == POLL_READ:
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select.select([conn.fileno()], [], [])
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elif state == POLL_WRITE:
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select.select([], [conn.fileno()], [])
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else:
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raise conn.OperationalError("bad state from poll: %s" % state)
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try:
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state = conn.poll()
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if state == POLL_OK:
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break
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elif state == POLL_READ:
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select.select([conn.fileno()], [], [])
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elif state == POLL_WRITE:
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select.select([], [conn.fileno()], [])
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else:
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raise conn.OperationalError("bad state from poll: %s" % state)
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except KeyboardInterrupt:
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conn.cancel()
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# the loop will be broken by a server error
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continue
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def _solve_conn_curs(conn_or_curs):
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