Re: [Python-Dev] Using Cython for developing a module to be used from postgreSQL/pl/python
Hannu Krosing, 31.03.2012 14:22: Has anyone used Cython for developing a module to be used from postgreSQL/pl/python. Something that calls back to PostgreSQL internals. Note that this is the CPython core developers mailing list, for which your question is off-topic. Please ask on the cython-users mailing list (see http://cython.org). Stefan ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Using Cython for developing a module to be used from postgreSQL/pl/python
On Sat, 2012-03-31 at 14:41 +0200, Stefan Behnel wrote: Hannu Krosing, 31.03.2012 14:22: Has anyone used Cython for developing a module to be used from postgreSQL/pl/python. Something that calls back to PostgreSQL internals. Note that this is the CPython core developers mailing list, for which your question is off-topic. Please ask on the cython-users mailing list (see http://cython.org). Thanks for the pointer ! Can you recommend a similar place for asking the same queston about ctypes ? That is using ctypes for calling back to outer c application which embeds the python interpreter. Stefan ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/hannu%40krosing.net ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Using Cython for developing a module to be used from postgreSQL/pl/python
Hannu Krosing ha...@krosing.net writes: Has anyone used Cython for developing a module to be used from postgreSQL/pl/python. Something that calls back to PostgreSQL internals. Are you aware that PostgreSQL has long provided Python as a language for writing stored procedures in the database? URL:http://www.postgresql.org/docs/current/static/plpython.html Does that meet your needs? -- \ “You've got to think about big things while you're doing small | `\ things, so that all the small things go in the right | _o__) direction.” —Alvin Toffler | Ben Finney ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Using Cython for developing a module to be used from postgreSQL/pl/python
On Sun, 2012-04-01 at 00:44 +1100, Ben Finney wrote:
Hannu Krosing ha...@krosing.net writes:
Has anyone used Cython for developing a module to be used from
postgreSQL/pl/python.
Something that calls back to PostgreSQL internals.
Are you aware that PostgreSQL has long provided Python as a language for
writing stored procedures in the database?
URL:http://www.postgresql.org/docs/current/static/plpython.html
Does that meet your needs?
Sure, I have even contributed code to it ;)
But what i want is some way to call _back_ into PostgreSQL to use its
internal functions from a module imported from pl/python.
I tried ctypes module and got a segfault when i used the following
create or replace function callback_to_postgres(rn_text text)
returns text
language plpythonu
as
$$
from ctypes import *
import struct
pg = cdll.LoadLibrary('/usr/lib/postgresql/9.1/bin/postmaster')
pg.pq_flush()
return rn_text
$$;
select send_raw_notice('do you see me?');
CRASHES HERE
I determined that the call to pg.pq_flush() was the one crashing the
backend, so I assume that cdll.LoadLibrary did not get the already
running backend, but loaded another copy of it as library.
Now I'm looking for a simplest way to do some C-wrapping. I have used
Cyuthon for wrapping simple library calls and I really don'r think there
would be hard problems doing this inside the postgreSQL extension build
framework.
I was just hoping that someboduy had already taken care of all the
nitty-gritty detaiuls of setting this up
---
Hannu Krosing
PostgreSQL Unlimited Scalability and Performance Consultant
2ndQuadrant Nordic
PG Admin Book: http://www.2ndQuadrant.com/books/
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Re: [Python-Dev] Using Cython for developing a module to be used from postgreSQL/pl/python
Can you recommend a similar place for asking the same queston about ctypes ? That is using ctypes for calling back to outer c application which embeds the python interpreter. ISTM that Postgres lists should be the best place for this kind of question. Alternatively, try python-list or db-sig. Regards, Martin ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
