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

From: Jeff Ross <jross(at)openvistas(dot)net>
To: pgsql-general(at)lists(dot)postgresql(dot)org
Subject: Re: After 10 -> 15 upgrade getting "cannot commit while a portal is pinned" on one python function
Date: 2024-03-28 00:53:12
Message-ID: f613ab3e-2393-473a-9a96-3b71471c950a@openvistas.net
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general


On 3/27/24 17:41, Adrian Klaver wrote:
> On 3/27/24 16:35, 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.
>
> I would start with:
>
> def logging(comment):
>     global database
>     <...>
>
Already removed that--thanks, though.

In response to

Browse pgsql-general by date

  From Date Subject
Next Message Jeff Ross 2024-03-28 01:00:16 Re: After 10 -> 15 upgrade getting "cannot commit while a portal is pinned" on one python function
Previous Message Adrian Klaver 2024-03-27 23:41:05 Re: After 10 -> 15 upgrade getting "cannot commit while a portal is pinned" on one python function