Re: [BUGS] BUG #7534: walreceiver takes long time to detect n/w breakdown

On Fri, Sep 14, 2012 at 10:01 PM, Amit kapila <amit(dot)kapila(at)huawei(dot)com> wrote:
>
> On Thursday, September 13, 2012 10:57 PM Fujii Masao
> On Thu, Sep 13, 2012 at 1:22 PM, Amit Kapila <amit(dot)kapila(at)huawei(dot)com> wrote:
>> On Wednesday, September 12, 2012 10:15 PM Fujii Masao
>> On Wed, Sep 12, 2012 at 8:54 PM, <amit(dot)kapila(at)huawei(dot)com> wrote:
>>>>> The following bug has been logged on the website:
>>>>
>>>>> Bug reference: 7534
>>>>> Logged by: Amit Kapila
>>>>> Email address: amit(dot)kapila(at)huawei(dot)com
>>>>> PostgreSQL version: 9.2.0
>>>>> Operating system: Suse 10
>>>>> Description:
>>>
>>>>> 1. Both master and standby machine are connected normally,
>>>>> 2. then you use the command: ifconfig ip down; make the network card of
>>>>> master and standby down,
>>>
>>>>> Observation
>>>>> master can detect connect abnormal, but the standby can't detect connect
>>>>> abnormal and show a connected channel long time.
>>
>>
>>> I would like to implement such feature for walreceiver, but there is one
>>> confusion that whether to use
>>> same configuration parameter(replication_timeout) for walrecevier as for
>>> master or introduce a new
>>> configuration parameter (receiver_replication_timeout).
>
>>I like the latter. I believe some users want to set the different
>>timeout values,
>>for example, in the case where the master and standby servers are placed in
>>the same room, but cascaded standby is placed in other continent.
>
> Thank you for your suggestion. I have implemented as per your suggestion to have separate timeout parameter for walreceiver.
> The main changes are:
> 1. Introduce a new configuration parameter wal_receiver_replication_timeout for walreceiver.
> 2. In function WalReceiverMain(), check if there is no communication till wal_receiver_replication_timeout, exit the walreceiver.
> This is same as walsender functionality.
>
> As this is a feature, So I am uploading the attached patch in coming CommitFest.
>
> Suggestions/Comments?

You also need to change walsender so that it periodically sends the heartbeat
message, like walreceiver does each wal_receiver_status_interval. Otherwise,
walreceiver will detect the timeout wrongly whenever there is no traffic in the
master.

Regards,

--
Fujii Masao