Re: Keepalive for max_standby_delay

On Sun, May 16, 2010 at 6:05 AM, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> Heikki Linnakangas wrote:
>> Simon Riggs wrote:
>>> WALSender sleeps even when it might have more WAL to send, it doesn't
>>> check it just unconditionally sleeps. At least WALReceiver loops until
>>> it has no more to receive. I just can't imagine why that's useful
>>> behaviour.
>>
>> Good catch. That should be fixed.
>>
>> I also note that walsender doesn't respond to signals, while it's
>> sending a large batch. That's analogous to the issue that was addressed
>> recently in the archiver process.
>
> Attached patch rearranges the walsender loops slightly to fix the above.
> XLogSend() now only sends up to MAX_SEND_SIZE bytes (== XLOG_SEG_SIZE /
> 2) in one round and returns to the main loop after that even if there's
> unsent WAL, and the main loop no longer sleeps if there's unsent WAL.
> That way the main loop gets to respond to signals quickly, and we also
> get to update the shared memory status and PS display more often when
> there's a lot of catching up to do.
>
> Comments

The main loop needs to respond to also the 'X' message from the standby
quickly?

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center