Re: replay pause vs. standby promotion

On 2020/03/20 15:22, Atsushi Torikoshi wrote:
> 
> On Fri, Mar 6, 2020 at 10:18 PM Fujii Masao <masao.fujii@oss.nttdata.com <mailto:masao.fujii@oss.nttdata.com>>
wrote:
> 
> 
>     OK, so patch attached.
> 
>     This patch causes, if a promotion is triggered while recovery is paused,
>     the paused state to end and a promotion to continue. OTOH, this patch
>     makes pg_wal_replay_pause() and _resume() throw an error if it's executed
>     while a promotion is ongoing. 
> 
>     Regarding recovery_target_action, if the recovery target is reached
>     while a promotion is ongoing, "pause" setting will act the same as "promote",
>     i.e., recovery will finish and the server will start to accept connections.
> 
>     To implement the above, I added new shared varible indicating whether
>     a promotion is triggered or not. Only startup process can update this shared
>     variable. Other processes like read-only backends can check whether
>     promotion is ongoing, via this variable.
> 
>     I added new function PromoteIsTriggered() that returns true if a promotion
>     is triggered. Since the name of this function and the existing function
>     IsPromoteTriggered() are confusingly similar, I changed the name of
>     IsPromoteTriggered() to IsPromoteSignaled, as more appropriate name.
> 
> 
> I've confirmed the patch works as you described above.
> And I also poked around it a little bit but found no problems.

Thanks for the review!
Barrying any objection, I will commit the patch.

Regards,

-- 
Fujii Masao
NTT DATA CORPORATION
Advanced Platform Technology Group
Research and Development Headquarters