From: Rob Sargent <robjsargent@gmail.com>
To: pgsql-general@lists.postgresql.org
Subject: Re: After 10 -> 15 upgrade getting "cannot commit while a portal is pinned" on one python function
Date: Wed, 27 Mar 2024 17:35:03 -0600
Message-ID: <98d3484a-0ce1-4c74-85d4-c053652c5b9d@gmail.com> (raw)
In-Reply-To: <45d75f81-0be1-4990-97a7-5b4fa0e37c65@openvistas.net>
References: <6960da61-8033-4067-84d1-d9257ce94870@openvistas.net>
<81c4556d-b599-4512-b6a2-7255f2a39089@aklaver.com>
<d553c7d6-8af9-4e93-892b-7dc65129b4a6@openvistas.net>
<37154728-4700-45b7-9261-72400c80b12b@aklaver.com>
<133886.1710975858@sss.pgh.pa.us>
<5ef96169-c11d-48de-b322-b7579bf56cc3@openvistas.net>
<3446817.1711575877@sss.pgh.pa.us>
<45d75f81-0be1-4990-97a7-5b4fa0e37c65@openvistas.net>
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.
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Subject: Re: After 10 -> 15 upgrade getting "cannot commit while a portal is pinned" on one python function
In-Reply-To: <98d3484a-0ce1-4c74-85d4-c053652c5b9d@gmail.com>
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