Re: Some problems of recovery conflict wait events

On 2020/03/04 13:27, Michael Paquier wrote:
> On Wed, Mar 04, 2020 at 01:13:19PM +0900, Masahiko Sawada wrote:
>> Yeah, so 0001 patch sets existing wait events to recovery conflict
>> resolution. For instance, it sets (PG_WAIT_LOCK | LOCKTAG_TRANSACTION)
>> to the recovery conflict on a snapshot. 0003 patch improves these wait
>> events by adding the new type of wait event such as
>> WAIT_EVENT_RECOVERY_CONFLICT_SNAPSHOT. Therefore 0001 (and 0002) patch
>> is the fix for existing versions and 0003 patch is an improvement for
>> only PG13. Did you mean even 0001 patch doesn't fit for back-patching?

Yes, it looks like a improvement rather than bug fix.

> I got my eyes on this patch set.  The full patch set is in my opinion
> just a set of improvements, and not bug fixes, so I would refrain from
> back-backpatching.

I think that the issue (i.e., "waiting" is reported twice needlessly
in PS display) that 0002 patch tries to fix is a bug. So it should be
fixed even in the back branches.

Regards,

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