Previously, plpython was in the habit of allocating a lot of stuff in
TopMemoryContext, and it was very slipshod about making sure that stuff
got cleaned up; in particular, use of TopMemoryContext as fn_mcxt for
function calls represents an unfixable leak, since we generally don't
know what the called function might have allocated in fn_mcxt. This
results in session-lifespan leakage in certain usage scenarios, as for
example in a case reported by Ed Behn back in July.
To fix, get rid of all the retail allocations in TopMemoryContext.
All long-lived allocations are now made in sub-contexts that are
associated with specific objects (either pl/python procedures, or
Python-visible objects such as cursors and plans). We can clean these
up when the associated object is deleted.
I went so far as to get rid of PLy_malloc completely. There were a
couple of places where it could still have been used safely, but on
the whole it was just an invitation to bad coding.
Haribabu Kommi, based on a draft patch by Heikki Linnakangas;
some further work by me
This provides a mechanism for specifying conversions between SQL data
types and procedural languages. As examples, there are transforms
for hstore and ltree for PL/Perl and PL/Python.
reviews by Pavel Stěhule and Andres Freund
This moves the code around from one huge file into hopefully logical
and more manageable modules. For the most part, the code itself was
not touched, except: PLy_function_handler and PLy_trigger_handler were
renamed to PLy_exec_function and PLy_exec_trigger, because they were
not actually handlers in the PL handler sense, and it makes the naming
more similar to the way PL/pgSQL is organized. The initialization of
the procedure caches was separated into a new function
init_procedure_caches to keep the hash tables private to
plpy_procedures.c.
Jan Urbański and Peter Eisentraut
