RE: [Proposal] Add foreign-server health checks infrastructure

Hi,


On Wednesday, October 5, 2022 6:27 PM kuroda.hayato@fujitsu.com <kuroda.hayato@fujitsu.com> wrote:
> Thanks for giving many comments! Based on off and on discussions, I modified
> my patch.
Thank you for your patch set !

While reviewing and testing the new v16, I've met a possible issue
by slightly adjusting the scenario written in [1].

I mainly followed the steps there and
replaced the command "SELECT" for the remote table at 6-9 with "INSERT" command.
Then, after waiting for few seconds, the "COMMIT" succeeded like below output,
even after the server stop of the worker side.

After the transaction itself, any reference to the remote table fails.
Note that the local table has some data initially in my test.

postgres=# begin;
BEGIN
postgres=*# insert into remote values (-1000);
INSERT 0 1
postgres=*# select * from local;
 number 
--------
    101
    102
    103
    104
    105
(5 rows)

postgres=*# commit;
COMMIT
postgres=# select * from remote;
ERROR:  could not connect to server "my_external_server"
DETAIL:  connection to server on socket "/tmp/.s.PGSQL.9999" failed: No such file or directory
        Is the server running locally and accepting connections on that socket?


Additionally, the last reference "SELECT" which failed above can succeed,
if I restart the worker server before the "SELECT" command to the remote table.
This means the transaction looks successful but the data isn't there ?
Could you please have a look at this issue ?


[1] - https://www.postgresql.org/message-id/TYAPR01MB58662CD4FD98AA475B3D10F9F59B9%40TYAPR01MB5866.jpnprd01.prod.outlook.com


Best Regards,
	Takamichi Osumi