Re: wal stats questions

On 2021-04-16 10:27, Masahiro Ikeda wrote:
> On 2021/04/13 9:33, Fujii Masao wrote:
>>
>>
>> On 2021/03/30 20:37, Masahiro Ikeda wrote:
>>> OK, I added the condition to the fast-return check. I noticed that I
>>> misunderstood that the purpose is to avoid expanding a clock check
>>> using WAL
>>> stats counters. But, the purpose is to make the conditions stricter,
>>> right?
>>
>> Yes. Currently if the following condition is false even when the WAL
>> counters
>> are updated, nothing is sent to the stats collector. But with your
>> patch,
>> in this case the WAL stats are sent.
>>
>>     if ((pgStatTabList == NULL || pgStatTabList->tsa_used == 0) &&
>>         pgStatXactCommit == 0 && pgStatXactRollback == 0 &&
>>         !have_function_stats && !disconnect)
>>
>> Thanks for the patch! It now fails to be applied to the master
>> cleanly.
>> So could you rebase the patch?
>
> Thanks for your comments!
> I rebased it.

Thanks for working on this!

I have some minor comments on
performance-improvements-of-reporting-wal-stats-without-introducing-a-new-variable.patch.

177 @@ -3094,20 +3066,33 @@ pgstat_report_wal(void)
178 * Return true if the message is sent, and false otherwise.

Since you changed the return value to void, it seems the description is
not necessary anymore.

208 + * generate wal records. 'wal_writes' and 'wal_sync' are
zero means the

It may be better to change 'wal_writes' to 'wal_write' since single
quotation seems to mean variable name.

234 + * set the counters related to generated WAL data if the
counters are

set -> Set?

Regards,