The following bug has been logged online: Bug reference: 5842 Logged by: Daniel Popowich Email address: danielpopow...@gmail.com PostgreSQL version: 8.4.6 Operating system: x86_64-pc-linux-gnu (Ubuntu 10.04.1) Description: Memory leak in PL/Python when taking slices of results Details:
There is a memory leak in PL/Python when taking slices of results. This was first discussed in pgsql-general: http://archives.postgresql.org/pgsql-general/2011-01/msg00367.php Thanks to Alex Hunsaker for pinpointing the problem to slices. The following code (a modification of Alex's) demonstrates the problem well...in a database with plpythonu installed: -- leaks big time CREATE or replace FUNCTION py_leak() RETURNS void LANGUAGE plpythonu AS $$ results = plpy.execute("""select generate_series(0, 1000000)""") slice_creates_leak = results[:] for r in slice_creates_leak: pass return $$; -- does not leak CREATE or replace FUNCTION py_no_leak() RETURNS void LANGUAGE plpythonu AS $$ results = plpy.execute("""select generate_series(0, 1000000)""") for noleak in results: pass return $$; I traced the bug to PLy_result_slice() in src/pl/plpython/plpython.c. That function calls the python API function PyList_GetSlice() and erroneously increments the reference count before returning the result to the caller. PyList_GetSlice returns a *new* reference, not a borrowed one, so it should just return the object as-is. A patch is attached below. Cheers, Dan Popowich ---------------------------------------------------------------------- *** src/pl/plpython/plpython.c~ 2010-12-13 21:59:19.000000000 -0500 --- src/pl/plpython/plpython.c 2011-01-18 11:18:28.857831733 -0500 *************** *** 2328,2341 **** static PyObject * PLy_result_slice(PyObject *arg, Py_ssize_t lidx, Py_ssize_t hidx) { - PyObject *rv; PLyResultObject *ob = (PLyResultObject *) arg; ! rv = PyList_GetSlice(ob->rows, lidx, hidx); ! if (rv == NULL) ! return NULL; ! Py_INCREF(rv); ! return rv; } static int --- 2328,2336 ---- static PyObject * PLy_result_slice(PyObject *arg, Py_ssize_t lidx, Py_ssize_t hidx) { PLyResultObject *ob = (PLyResultObject *) arg; ! return PyList_GetSlice(ob->rows, lidx, hidx); } static int -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
