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From: Bossart, Nathan <[email protected]>
To: Bharath Rupireddy <[email protected]>
To: Julien Rouhaud <[email protected]>
Cc: Michael Paquier <[email protected]>
Cc: Kyotaro Horiguchi <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Add checkpoint and redo LSN to LogCheckpointEnd log message
Date: Thu, 20 Jan 2022 00:36:32 +0000
Message-ID: <[email protected]> (raw)
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On 1/3/22, 5:52 PM, "Kyotaro Horiguchi" <[email protected]> wrote:
> It seems to me "LSN" or just "location" is more confusing or
> mysterious than "REDO LSN" for the average user. If we want to avoid
> being technically too detailed, we would use just "start LSN=%X/%X,
> end LSN=%X/%X".  And it is equivalent to "WAL range=[%X/%X, %X/%X]"..

My first instinct was that this should stay aligned with
pg_controldata, but that would mean using "location=%X/%X, REDO
location=%X/%X," which doesn't seem terribly descriptive.  IIUC the
"checkpoint location" is the LSN of the WAL record for the checkpoint,
and the "checkpoint's REDO location" is the LSN where checkpoint
creation began (i.e., what you must retain for crash recovery).  My
vote is for "start=%X/%X, end=%X/%X."

Nathan

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