Re: After 10 -> 15 upgrade getting "cannot commit while a portal is pinned" on one python function

On 3/27/24 17:35, Rob Sargent wrote:
>
>
> On 3/27/24 17:05, Jeff Ross wrote:
>>
>> On 3/27/24 15:44, Tom Lane wrote:
>>
>>> Perhaps "pinned" in the error message means "open"?
>>> No, it means "pinned" ... but I see that plpython pins the portal
>>> underlying any PLyCursor object it creates. Most of our PLs do
>>> that too, to prevent a portal from disappearing under them (e.g.
>>> if you were to try to close the portal directly from SQL rather
>>> than via whatever mechanism the PL wants you to use).
>>>
>>>> I added a cursor.close() as the last line called in that function and it
>>>> works again.
>>> It looks to me like PLy_cursor_close does pretty much exactly the same
>>> cleanup as PLy_cursor_dealloc, including unpinning and closing the
>>> underlying portal. I'm far from a Python expert, but I suspect that
>>> the docs you quote intend to say "cursors are disposed of when Python
>>> garbage-collects them", and that the reason your code is failing is
>>> that there's still a reference to the PLyCursor somewhere after the
>>> plpython function exits, perhaps in a Python global variable.
>>>
>>> regards, tom lane
>>>
>>>
>> Thank you for your reply, as always, Tom!
>>
>> Debugging at this level might well be over my paygrade ;-)
>>
>> I just happy that the function works again, and that I was able to
>> share a solution to this apparently rare error with the community.
>>
>> Jeff
>>
> My read of Tom's reply suggests you still have work to do to find the
> other "reference" holding on to your cursor.

Yes, my read was the same.

There are exactly 3 references to that cursor now that I added the
close() at the end.

Here are the first 2 (cursor renamed from the code I posted):

        plpy_cursor = plpy.cursor(schemas_query)
        while True:
            schema_rows = plpy_cursor.fetch(100)

The last is:

        plpy_cursor.close()

I don't know how to proceed further.