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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/src/extras.rst | 3 | ||||
| -rw-r--r-- | doc/src/faq.rst | 31 |
2 files changed, 34 insertions, 0 deletions
diff --git a/doc/src/extras.rst b/doc/src/extras.rst index 36ef013..0e21ae5 100644 --- a/doc/src/extras.rst +++ b/doc/src/extras.rst @@ -611,3 +611,6 @@ Coroutine support .. autofunction:: wait_select(conn) + .. versionchanged:: 2.6.2 + allow to cancel a query using :kbd:`Ctrl-C`, see + :ref:`the FAQ <faq-interrupt-query>` for an example. diff --git a/doc/src/faq.rst b/doc/src/faq.rst index 8f2f1ec..69273ba 100644 --- a/doc/src/faq.rst +++ b/doc/src/faq.rst @@ -223,6 +223,37 @@ What are the advantages or disadvantages of using named cursors? little memory on the client and to skip or discard parts of the result set. +.. _faq-interrupt-query: +.. cssclass:: faq + +How do I interrupt a long-running query in an interactive shell? + Normally the interactive shell becomes unresponsive to :kbd:`Ctrl-C` when + running a query. Using a connection in green mode allows Python to + receive and handle the interrupt, although it may leave the connection + broken, if the async callback doesn't handle the `!KeyboardInterrupt` + correctly. + + Starting from psycopg 2.6.2, the `~psycopg2.extras.wait_select` callback + can handle a :kbd:`Ctrl-C` correctly. For previous versions, you can use + `this implementation`__. + + .. __: http://initd.org/psycopg/articles/2014/07/20/cancelling-postgresql-statements-python/ + + .. code-block:: pycon + + >>> psycopg2.extensions.set_wait_callback(psycopg2.extensions.wait_select) + >>> cnn = psycopg2.connect('') + >>> cur = cnn.cursor() + >>> cur.execute("select pg_sleep(10)") + ^C + Traceback (most recent call last): + File "<stdin>", line 1, in <module> + QueryCanceledError: canceling statement due to user request + + >>> cnn.rollback() + >>> # You can use the connection and cursor again from here + + .. _faq-compile: Problems compiling and deploying psycopg2 |