Re: [BUGS] BUG #7534: walreceiver takes long time to detect n/w breakdown - Mailing list pgsql-hackers

From Fujii Masao
Subject Re: [BUGS] BUG #7534: walreceiver takes long time to detect n/w breakdown
Date
Msg-id CAHGQGwGG=UxNOJX0V966CftRm4C_54XDfaR2TRzWXysFFQcJSw@mail.gmail.com
Whole thread Raw
In response to Re: [BUGS] BUG #7534: walreceiver takes long time to detect n/w breakdown  (Amit kapila <amit.kapila@huawei.com>)
Responses Re: [BUGS] BUG #7534: walreceiver takes long time to detect n/w breakdown  (Amit kapila <amit.kapila@huawei.com>)
List pgsql-hackers
On Fri, Sep 14, 2012 at 10:01 PM, Amit kapila <amit.kapila@huawei.com> wrote:
>
> On Thursday, September 13, 2012 10:57 PM Fujii Masao
> On Thu, Sep 13, 2012 at 1:22 PM, Amit Kapila <amit.kapila@huawei.com> wrote:
>> On Wednesday, September 12, 2012 10:15 PM Fujii Masao
>> On Wed, Sep 12, 2012 at 8:54 PM,  <amit.kapila@huawei.com> wrote:
>>>>> The following bug has been logged on the website:
>>>>
>>>>> Bug reference:      7534
>>>>> Logged by:          Amit Kapila
>>>>> Email address:      amit.kapila@huawei.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



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