public inbox for [email protected]  

help / color / mirror / Atom feed

From: Bharath Rupireddy <[email protected]>
To: Bossart, Nathan <[email protected]>
Cc: 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, 27 Jan 2022 20:37:37 +0530
Message-ID: <CALj2ACUfLrN8XGn0ZNrAou5eoDwMnFGnDE9rhcs8==jmtSd4WA@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <CALj2ACWt6kqriAHrO+AJj+OmP=suwbktHT5JoYAn-nqZe2gd2g@mail.gmail.com>
	<[email protected]>
	<[email protected]>
	<CALj2ACXzv6FJNbTnP9uYsPXFeA4UcugSWDecxr19SjFCUCxP-g@mail.gmail.com>
	<CALj2ACUP84UYSimewLSs8--rT9dUTA7CUYTgXTnEb-2iHkc9wA@mail.gmail.com>
	<CAOBaU_aefLN5Gze52os5JzkNR_Fc+bJHPk=m67zov33-66MfZw@mail.gmail.com>
	<CALj2ACUGutu6As-9p76Ta2bV59J97fbiCc9NSzaWXqxPJdMvag@mail.gmail.com>
	<CALj2ACVM4wjS+wiNZf4ssdNMhSR-XUhR99fYbV=pC9_-=5wCtw@mail.gmail.com>
	<[email protected]>

On Thu, Jan 20, 2022 at 6:06 AM Bossart, Nathan <[email protected]> wrote:
>
> 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."

I'm still not clear how the REDO location can be treated as a start
LSN? Can someone throw some light one what this checkpoint's REDO
location is?

Regards,
Bharath Rupireddy.

view thread (15+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
  Subject: Re: Add checkpoint and redo LSN to LogCheckpointEnd log message
  In-Reply-To: <CALj2ACUfLrN8XGn0ZNrAou5eoDwMnFGnDE9rhcs8==jmtSd4WA@mail.gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox