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

On 2021/01/30 9:28, Bharath Rupireddy wrote:
> On Sat, Jan 30, 2021 at 12:14 AM Fujii Masao
> <masao(dot)fujii(at)oss(dot)nttdata(dot)com> wrote:
>> + /*
>> + * It doesn't make sense to show this entry in the output with a
>> + * NULL server_name as it will be closed at the xact end.
>> + */
>> + continue;
>>
>> -1 with this change because I still think that it's more useful to list
>> all the open connections.
>
> If postgres_fdw_get_connections doesn't have a "valid" column, then I
> thought it's better not showing server_name NULL in the output.

Or if we don't have strong reason to remove "valid" column,
the current design is enough?

> Do you
> think that we need to output some fixed strings for such connections
> like "<unknown server>" or "<server doesn't exist>" or "<dropped
> server>" or "<server information not available>"? I'm not sure whether
> we are allowed to have fixed strings as column output.
>
>> This makes me think that more discussion would be necessary before
>> changing the interface of postgres_fdw_get_connections(). On the other
>> hand, we should address the issue ASAP to make the buildfarm member fine.
>> So at first I'd like to push only the change of regression test.
>> Patch attached. I tested it both with CLOBBER_CACHE_ALWAYS set and unset,
>> and the results were stable.
>
> Thanks, the postgres_fdw.patch looks good to me.

Thanks for checking the patch! I pushed that.

Regards,

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