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

On Wed, Oct 17, 2012 at 8:46 PM, Amit Kapila <amit.kapila@huawei.com> wrote:
>> On Monday, October 15, 2012 3:43 PM Heikki Linnakangas wrote:
>> On 13.10.2012 19:35, Fujii Masao wrote:
>> > On Thu, Oct 11, 2012 at 11:52 PM, Heikki Linnakangas
>> > <hlinnakangas@vmware.com>  wrote:
>> >> Ok, thanks. Committed.
>> >
>> > I found one typo. The attached patch fixes that typo.
>>
>> Thanks, fixed.
>>
>> > ISTM you need to update the protocol.sgml because you added
>> > the field 'replyRequested' to WalSndrMessage and StandbyReplyMessage.
>
>
>>
>> > Is it worth adding the same mechanism (send back the reply immediately
>> > if walsender request a reply) into pg_basebackup and pg_receivexlog?
>>
>> Good catch. Yes, they should be taught about this too. I'll look into
>> doing that too.
>
> If you have not started and you don't have objection, I can pickup this to
> complete it.
>
> For both (pg_basebackup and pg_receivexlog), we need to get a timeout
> parameter from user in command line, as
> there is no conf file here. New Option can be -t (parameter name can be
> recvtimeout).
>
> The main changes will be in function ReceiveXlogStream(), it is a common
> function for both
> Pg_basebackup and pg_receivexlog. Handling will be done in same way as we
> have done in walreceiver.
>
> Suggestions/Comments?

Before implementing the timeout parameter, I think that it's better to change
both pg_basebackup background process and pg_receivexlog so that they
send back the reply message immediately when they receive the keepalive
message requesting the reply. Currently, they always ignore such keepalive
message, so status interval parameter (-s) in them always must be set to
the value less than replication timeout. We can avoid this troublesome
parameter setting by introducing the same logic of walreceiver into both
pg_basebackup background process and pg_receivexlog.

Regards,

-- 
Fujii Masao