From: Christoph Berg <myon@debian.org>
To: Nathan Bossart <nathandbossart@gmail.com>
Cc: Fujii Masao <masao.fujii@oss.nttdata.com>
Cc: Andres Freund <andres@anarazel.de>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: CHECKPOINT unlogged data
Date: Wed, 11 Jun 2025 15:45:46 +0200
Message-ID: <aEmIijETyhj9DsWG@msg.df7cb.de> (raw)
In-Reply-To: <aEMYYEkQb2VeQoBo@nathan>
References: <vp4cewuyo2cw4fk5sxjaovllhe3dscixxo2utu3cgqhzydrqec@wc2nhgx4khpk>
<aDnl5N1u7UBYVaSt@nathan>
<aDnpeJ99HhoMgJ40@msg.df7cb.de>
<7x6gsmev36zzh6lfzydkddbhpnxqgu2k2l2ci2k6foxhrstvj2@bn55g54wjrl4>
<aEK88AwaYBNK1p-O@msg.df7cb.de>
<fc1ed66f-e95a-4d10-a4f7-7fa4bb9a7084@oss.nttdata.com>
<aEL6sDr9RxdSkPm-@msg.df7cb.de>
<aEMIrLUDOKgmE_0P@nathan>
<aEMVRbmqqg-aaxAN@msg.df7cb.de>
<aEMYYEkQb2VeQoBo@nathan>
Re: Nathan Bossart
> That seems like a good idea to me. I'm tempted to say that "fast" more
> accurately describes what's happening than "immediate." "Immediate" sounds
> like it happens instantaneously, but it's actually just happening "fast,"
> i.e., as fast as possible.
Ack.
> > #define CHECKPOINT_FLUSH_ALL 0x0010 /* Flush all pages, including those
> > * belonging to unlogged tables */
> >
> > Maybe CHECKPOINT_FLUSH_UNLOGGED would be more explicit?
>
> WFM.
Do we want to change the checkpoint log message (and the new options)
only, or include the CHECKPOINT_* flags? (I would guess there aren't
many external users of these flags, but mmmv.)
> I thought it would make sense to put it closer to where these options are
> described, since it'll be most evident for manually-initiated checkpoints.
Ack, I'll add that.
> >> We might also want to make sure it's clear that CHECKPOINT does nothing if
> >> there's been no database activity since the last one (or, in the case of a
> >> restartpoint, if there hasn't been a checkpoint record).
> >
> > That's taken care of by "force":
> >
> > #define CHECKPOINT_FORCE 0x0008 /* Force even if no activity */
>
> Oh, I see that we always specify that for CHECKPOINT commands, except for
> restartpoints. IIRC even if you do specify CHECKPOINT_FORCE for a
> restartpoint, it'll have no effect. It's proably worth mentioning that
> case, at least.
Right, will do.
Christoph
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: pgsql-hackers@postgresql.org
Cc: myon@debian.org, nathandbossart@gmail.com, masao.fujii@oss.nttdata.com, andres@anarazel.de, pgsql-hackers@lists.postgresql.org
Subject: Re: CHECKPOINT unlogged data
In-Reply-To: <aEmIijETyhj9DsWG@msg.df7cb.de>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox