Re: [PATCH] postgres_fdw connection caching - cause remote sessions linger till the local session exit

On 2021/04/02 1:13, Bharath Rupireddy wrote:
> On Thu, Apr 1, 2021 at 8:56 PM Fujii Masao <masao.fujii@oss.nttdata.com> wrote:
>>
>>> Attaching v21 patch set, rebased onto the latest master.
>>
>> I agree to add the server-level option. But I'm still not sure if it's good idea to also expose that option as GUC.
Isn'tthe server-level option enough for most cases?
 
>>
>> Also it's strange to expose only this option as GUC while there are other many postgres_fdw options?
>>
>> With v21-002 patch, even when keep_connections GUC is disabled, the existing open connections are not close
immediately.Only connections used in the transaction are closed at the end of that transaction. That is, the existing
connectionsthat no transactions use will never be closed. I'm not sure if this behavior is intuitive for users.
 
>>
>> Therefore for now I'm thinking to support the server-level option at first... Then if we find it's not enough for
mostcases in practice, I'd like to consider to expose postgres_fdw options including keep_connections as GUC.
 
>>
>> Thought?
> 
> +1 to have only a server-level option for now and if the need arises
> we could expose it as a GUC.
> 
>> BTW these patches fail to be applied to the master because of commit 27e1f14563. I updated and simplified the 003
patch.Patch attached.
 
> 
> Thanks for updating the patch. It looks good to me. Just a minor
> change, instead of using "true" and "off" for the option, I used "on"
> and "off" in the docs. Attaching v23.

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