Re: fetchall() never returns

On Mon, Aug 16, 2010 at 2:57 AM, Rob Brown-Bayliss
<[email protected]> wrote:
> Hi
>
> I have a problem with what appears to be fetchall() never returning or
> not timing out.

Can you see what is happening in the server while the query is
running? E.g. you can execute a "select * from pg_stat_activity" in a
separate connection and check if your query appears there.

In order to cancel a running query you may execute the
pg_cancel_backend function(pid) [1] in another connection, using as
pid the one returned by conn.get_backend_pid() [2] on the connection
to time out (retrieved before running the query of course)

Because python is stuck with the execute, you may need a separate
thread to send the cancel, otherwise you may try with a signal: see
for instance the recipe [3].

[1] http://www.postgresql.org/docs/8.3/static/functions-admin.html#FUNCTIONS-ADMIN-SIGNAL-TABLE
[2] http://initd.org/psycopg/docs/connection.html#connection.get_backend_pid
[3] http://stackoverflow.com/questions/492519/timeout-on-a-python-function-call/494273#494273

-- Daniele