Re: Synchronous replication

Fujii Masao <masao.fujii@gmail.com>

From: Fujii Masao <masao.fujii@gmail.com>
To: Yeb Havinga <yebhavinga@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2010-07-27T11:29:29Z
Lists: pgsql-hackers
On Tue, Jul 27, 2010 at 7:39 PM, Yeb Havinga <yebhavinga@gmail.com> wrote:
> Fujii Masao wrote:
>>
>> The attached patch changes the backend so that it signals walsender to
>> wake up from the sleep and send WAL immediately. It doesn't include any
>> other synchronous replication stuff.
>>
>
> Hello Fujii,

Thanks for the review!

> I noted the changes in XlogSend where instead of *caughtup = true/false it
> now returns !MyWalSnd->sndrqst. That value is initialized to false in that
> procedure and it cannot be changed to true during execution of that
> procedure, or can it?

That value is set to true in WalSndWakeup(). If WalSndWakeup() is called
after initialization of that value in XLogSend(), *caughtup is set to false.

Regards,

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