Re: cache lookup failed from empty plpythonu function

On 2013-01-25 21:07:51 +0100, Andres Freund wrote:
> On 2013-01-25 14:51:39 -0500, Tom Lane wrote:
> > Andres Freund <andres@2ndquadrant.com> writes:
> > > Its slightly more complex than just making it one hash table with an
> > > extended key. When validating a trigger function we don't have a
> > > relation to do the cache lookup. I chose to handle that case by not
> > > doing a cache lookup at all in that case which imo is a sensible
> > > choice.
> >
> > Seems fair.  However ... why is it safe for PLy_procedure_create to be
> > using the same name for multiple instances of a trigger function?
> > Should we not be including the rel OID when building the procName
> > string?
>
> I don't think its a problem, given the way python works I am pretty sure
> it will result in independent functions.
>
> Each PLy_procedure_compile will run the source code in a copy of
> PLy_interp_globals, therefore the independent comilitions shouldn't
> affect each other.
>
> I am not sure why it builds the call to the function via eval'ing a
> "$funcname()" instead of using the result of PyRun_String which will
> return a reference to the function, but thats an independent issue.
>
> Now I think an argument can be made that it would be nicer for debugging
> purposes to have clearly distinguishable function names, but I
> personally never needed it and it probably wouldn't be something to
> backpatch. People might rely on those function names.

Just for fun I tried how easy it is to have some fun with the function
name. Guess what happens when the attached sql file is executed ;)

quite possibly doesn't work if copied from here but for quicker viewing:

CREATE OR REPLACE FUNCTION "foo():
    pass

import os
os._exit(1)
def "() RETURNS void LANGUAGE plpythonu AS $$pass$$;

Yep:
LOG:  server process (PID 29317) exited with exit code 1
DETAIL:  Failed process was running: CREATE OR REPLACE FUNCTION "foo():
        pass

    import os
    os._exit(1)
    def "() RETURNS void LANGUAGE plpythonu AS $$pass$$;
LOG:  terminating any other active server processes
WARNING:  terminating connection because of crash of another server process
DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because
anotherserver process exited abnormally and possibly corrupted shared memory. 
HINT:  In a moment you should be able to reconnect to the database and repeat your command.

Anyway, back to more sensible things ;)

Greetings,

Andres Freund

--
 Andres Freund                       http://www.2ndQuadrant.com/
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