Re: About to add WAL write/fsync statistics to pg_stat_wal view

From: Masahiro Ikeda <ikedamsh(at)oss(dot)nttdata(dot)com>
To: Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, Li Japin <japinli(at)hotmail(dot)com>, kuroda(dot)hayato(at)fujitsu(dot)com, "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com>
Subject: Re: About to add WAL write/fsync statistics to pg_stat_wal view
Date: 2021-02-15 02:32:12
Message-ID: 57870df084d7f0462a29b9a9c8d49d44@oss.nttdata.com
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On 2021-02-08 13:01, Fujii Masao wrote:
> On 2021/02/05 8:45, Masahiro Ikeda wrote:
>> I pgindented the patches.
>
> Thanks for updating the patches!

Thanks for checking the patches.

> + <function>XLogWrite</function>, which nomally called by an
> + <function>issue_xlog_fsync</function>, which nomally called by
> an
>
> Typo: "nomally" should be "normally"?

Yes, I'll fix it.

> + <function>XLogFlush</function> request(see <xref
> linkend="wal-configuration"/>)
> + <function>XLogFlush</function> request(see <xref
> linkend="wal-configuration"/>),
>
> Isn't it better to add a space character just after "request"?

Thanks, I'll fix it.

> + INSTR_TIME_SET_CURRENT(duration);
> + INSTR_TIME_SUBTRACT(duration, start);
> + WalStats.m_wal_write_time = INSTR_TIME_GET_MICROSEC(duration);
>
> If several cycles happen in the do-while loop, m_wal_write_time should
> be
> updated with the sum of "duration" in those cycles instead of
> "duration"
> in the last cycle? If yes, "+=" should be used instead of "=" when
> updating
> m_wal_write_time?
> + INSTR_TIME_SET_CURRENT(duration);
> + INSTR_TIME_SUBTRACT(duration, start);
> + WalStats.m_wal_sync_time = INSTR_TIME_GET_MICROSEC(duration);
>
> Also "=" should be "+=" in the above?

Yes, they are my mistake when changing the unit from milliseconds to
microseconds.

Regards,
--
Masahiro Ikeda
NTT DATA CORPORATION

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