Message-ID: <2160c6db-079a-be7c-df96-6c5cb21c03cf@oss.nttdata.com>
Date: Sun, 18 Sep 2022 12:39:14 +0900
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0)
 Gecko/20100101 Thunderbird/91.13.0
Subject: Re: [Proposal] Add foreign-server health checks infrastructure
Content-Language: en-US
To: "kuroda.hayato@fujitsu.com" <kuroda.hayato@fujitsu.com>,
 'Kyotaro Horiguchi' <horikyota.ntt@gmail.com>
Cc: "pgsql-hackers@lists.postgresql.org"
 <pgsql-hackers@lists.postgresql.org>,
 "Shinya11.Kato@oss.nttdata.com" <Shinya11.Kato@oss.nttdata.com>,
 "zyu@yugabyte.com" <zyu@yugabyte.com>
References: <be053d3d-b195-0852-4c29-0c67bb640b48@oss.nttdata.com>
 <20220216.115058.1615761004338301624.horikyota.ntt@gmail.com>
 <TYAPR01MB58661B088B6066282824ADD9F5369@TYAPR01MB5866.jpnprd01.prod.outlook.com>
 <20220217.170832.627054018291482509.horikyota.ntt@gmail.com>
 <TYAPR01MB58664E79C4728A6FFEA46F94F53B9@TYAPR01MB5866.jpnprd01.prod.outlook.com>
 <379473f3-ed14-a19f-92ed-91dc73d430d3@oss.nttdata.com>
 <TYAPR01MB5866FF28C802916242F1B492F53B9@TYAPR01MB5866.jpnprd01.prod.outlook.com>
 <TYAPR01MB5866C6278B6386672B35F624F53B9@TYAPR01MB5866.jpnprd01.prod.outlook.com>
 <4968741d-f32c-a251-efc9-2d3db83e6891@oss.nttdata.com>
 <TYAPR01MB5866FC683843ED8BD09505FEF53D9@TYAPR01MB5866.jpnprd01.prod.outlook.com>
 <TYAPR01MB5866982FC21ABE5DF3C1E3A2F5059@TYAPR01MB5866.jpnprd01.prod.outlook.com>
From: Fujii Masao <masao.fujii@oss.nttdata.com>
In-Reply-To: 
 <TYAPR01MB5866982FC21ABE5DF3C1E3A2F5059@TYAPR01MB5866.jpnprd01.prod.outlook.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Archived-At: 
 <https://www.postgresql.org/message-id/2160c6db-079a-be7c-df96-6c5cb21c03cf%40oss.nttdata.com>
Precedence: bulk


On 2022/03/04 15:17, kuroda.hayato@fujitsu.com wrote:
> Hi Hackers,
> 
>> It's not happy, but I'm not sure about a good solution. I made a timer reschedule
>> if connection lost had detected. But if queries in the transaction are quite short,
>> catching SIGINT may be fail.
> 
> Attached uses another way: sets pending flags again if DoingCommandRead is true.
> If a remote server goes down while it is in idle_in_transaction,
> next query will fail because of ereport(ERROR).
> 
> How do you think?

Sounds ok to me.

Thanks for updating the patches!

These failed to be applied to the master branch cleanly. Could you update them?

+      this option relies on kernel events exposed by Linux, macOS,

s/this/This

+		GUC_check_errdetail("pgfdw_health_check_interval must be set to 0 on this platform");

The actual parameter name "postgres_fdw.health_check_interval"
should be used for the message instead of internal variable name.

+		/* Register a timeout for checking remote servers */
+		pgfdw_health_check_timeout = RegisterTimeout(USER_TIMEOUT, pgfdw_connection_check);

This registered signal handler does lots of things. But that's not acceptable
and they should be performed outside signal handler. No?

Regards,

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