Re: postgres_fdw - cached connection leaks if the associated user mapping/foreign server is dropped

On 2020/12/24 23:30, Bharath Rupireddy wrote:
> On Thu, Dec 24, 2020 at 7:43 PM Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com> wrote:
>> Even when we're in the midst of transaction, if that transaction has not used
>> the cached connections yet, we close them immediately. So, to make the
>> comment more precise, what about updating the comment as follows?
>>
>> ---------------------
>> After a change to a pg_foreign_server or pg_user_mapping catalog entry,
>> close connections depending on that entry immediately if current
>> transaction has not used those connections yet. Otherwise, mark those
>> connections as invalid and then make pgfdw_xact_callback() close them
>> at the end of current transaction, since they cannot be closed in the midst
>> of a transaction using them. Closed connections will be remade at the next
>> opportunity if necessary.
>> ---------------------
>
> Done.
>
>> + /*
>> + * Close the connection if it's not in midst of a xact. Otherwise
>> + * mark it as invalid so that it can be disconnected at the end of
>> + * main xact in pgfdw_xact_callback().
>> + */
>>
>> Because of the same reason as the above, what about updating this comment
>> as follows?
>>
>> ---------------------
>> Close the connection immediately if it's not used yet in this transaction.
>> Otherwise mark it as invalid so that pgfdw_xact_callback() can close it
>> at the end of this transaction.
>> ---------------------
>
> Done.
>
> Attaching v3 patch. Please have a look. Thanks!

Thanks a lot! Barring any objection, I will commit this version.

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION