From: Daniel Gustafsson <daniel@yesql.se>
Message-Id: <A2DA6464-F27E-4545-9DE7-B61A6172DD18@yesql.se>
Content-Type: multipart/mixed;
	boundary="Apple-Mail=_D71CB3AD-5BAE-4741-AFCE-8001BABE111C"
Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3776.700.51.11.12\))
Subject: Re: Fix data checksum progress reporting docs
Date: Fri, 10 Jul 2026 12:00:33 +0200
In-Reply-To: 
 <CAHGQGwFsBjQs2fv7b72hxzGV_fJMh6LAg4E83pNfDOu1jVgWCA@mail.gmail.com>
Cc: "pgsql-docs@lists.postgresql.org" <pgsql-docs@lists.postgresql.org>
To: Fujii Masao <masao.fujii@gmail.com>
References: 
 <CAHGQGwHJHJYAkYZBi3_O13np-Rou9UL637=hB3Y_-qdCgcZn-w@mail.gmail.com>
 <E5A7D80B-A691-4DDE-9E90-19CC0ED0BFF5@yesql.se>
 <CAHGQGwEv-C9ia+rBYyePzO8F=5FVvS412ZqcOupazuOb5RafNg@mail.gmail.com>
 <8D4EF043-0DA9-4DF1-A28C-E3598167D1D2@yesql.se>
 <CAHGQGwFsBjQs2fv7b72hxzGV_fJMh6LAg4E83pNfDOu1jVgWCA@mail.gmail.com>
Archived-At: 
 <https://www.postgresql.org/message-id/A2DA6464-F27E-4545-9DE7-B61A6172DD18%40yesql.se>
Precedence: bulk


--Apple-Mail=_D71CB3AD-5BAE-4741-AFCE-8001BABE111C
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain;
	charset=utf-8

> On 10 Jul 2026, at 03:13, Fujii Masao <masao.fujii@gmail.com> wrote:
>=20
> On Thu, Jul 9, 2026 at 5:28=E2=80=AFPM Daniel Gustafsson =
<daniel@yesql.se> wrote:
>> You are absolutely right.  And when looking at it I think we can =
simplify the
>> entry a bit as well to make it fit the style of the page better.  =
What do you
>> think about the attached?
>=20
> Thanks for the patch! I like the overall approach.
> I just have a few minor comments.
>=20
> +     A set of
> +     <glossterm linkend=3D"glossary-background-worker">background
> worker</glossterm>
> +     processes which can enable, or disable, data checksums in a
>=20
> Wouldn't it be better to remove the two commas here?

Fixed.

> +     running cluster.  The process which coordinates the work is =
known as the
> +     <firstterm>data checksums worker launcher</firstterm> and the =
process
>=20
> Only the glossary seems to use the term "data checksums worker =
launcher".
> Wouldn't "data checksums launcher" (i.e., dropping "worker") be a =
better name?

Fixed.

> +     <firstterm>data checksums worker launcher</firstterm> and the =
process
> +     which operate on the individual databases is known as the
> +     <firstterm>data checksums worker</firstterm>.
>=20
> Shouldn't "the process which operate" be either "the process which =
operates"
> or "the processes which operate"? Since multiple data checksums =
workers
> can run, the latter seems more appropriate.

Currently the processing is limited to a single worker, so I think the =
proposed
wording is more appropriate.  Expanding the code to handle multiple =
parallel
workers was left as a future enhancement (it will perhaps require better =
IO
throttling etc).

> While looking at the related code, I also found that
> B_DATACHECKSUMSWORKER_LAUNCHER and B_DATACHECKSUMSWORKER_WORKER
> were added as BackendType entries in miscadmin.h. Since those entries =
appear
> under the comment for auxiliary processes, it could give the =
impression that
> the data checksums launcher and workers are auxiliary processes. To =
avoid
> that confusion, would it make sense to add a comment such as:
>=20
>    -------------------------
>            B_WAL_WRITER,
>=20
>    +       /*
>    +        * XXXXXXXXXX
>    +        */
>            B_DATACHECKSUMSWORKER_LAUNCHER,
>            B_DATACHECKSUMSWORKER_WORKER,
>    -------------------------

Fair point, see attached.

> BTW, I'm also wondering why dedicated BackendType entries were added =
for
> the data checksums processes, while other background workers don't =
have
> their own BackendType values.

They are need for the pgstat system though aren't they, or am I missing
something?

--
Daniel Gustafsson


--Apple-Mail=_D71CB3AD-5BAE-4741-AFCE-8001BABE111C
Content-Disposition: attachment;
	filename=v2-0002-Add-a-comment-to-distinguish-backend-types.patch
Content-Type: application/octet-stream;
	x-unix-mode=0644;
	name="v2-0002-Add-a-comment-to-distinguish-backend-types.patch"
Content-Transfer-Encoding: quoted-printable

=46rom=204c0ba4fd236548abfecdf0d6d242b3a57b2754f7=20Mon=20Sep=2017=20=
00:00:00=202001=0AFrom:=20Daniel=20Gustafsson=20=
<dgustafsson@postgresql.org>=0ADate:=20Fri,=2010=20Jul=202026=2011:37:06=20=
+0200=0ASubject:=20[PATCH=20v2=202/2]=20Add=20a=20comment=20to=20=
distinguish=20backend=20types=0A=0AThe=20data=20checksums=20entries=20=
were=20seemingly=20auxiliary=20processes=20from=0Areading=20the=20code,=20=
but=20they=20are=20in=20fact=20background=20workers.=20=20Add=20a=0A=
comment=20to=20clarify.=0A=0AReported-by:=20Fujii=20Masao=20=
<masao.fujii@gmail.com>=0ADiscussion:=20=
https://postgr.es/m/CAHGQGwFsBjQs2fv7b72hxzGV_fJMh6LAg4E83pNfDOu1jVgWCA@ma=
il.gmail.com=0A---=0A=20src/include/miscadmin.h=20|=201=20+=0A=201=20=
file=20changed,=201=20insertion(+)=0A=0Adiff=20--git=20=
a/src/include/miscadmin.h=20b/src/include/miscadmin.h=0Aindex=20=
7170a4bff98..16da60721bf=20100644=0A---=20a/src/include/miscadmin.h=0A=
+++=20b/src/include/miscadmin.h=0A@@=20-370,6=20+370,7=20@@=20typedef=20=
enum=20BackendType=0A=20=09B_WAL_SUMMARIZER,=0A=20=09B_WAL_WRITER,=0A=20=0A=
+=09/*=20Background=20worker=20processes=20*/=0A=20=09=
B_DATACHECKSUMSWORKER_LAUNCHER,=0A=20=09B_DATACHECKSUMSWORKER_WORKER,=0A=20=
=0A--=20=0A2.39.3=20(Apple=20Git-146)=0A=0A=

--Apple-Mail=_D71CB3AD-5BAE-4741-AFCE-8001BABE111C
Content-Disposition: attachment;
	filename=v2-0001-doc-Fix-glossary-entry-for-data-checksums-workers.patch
Content-Type: application/octet-stream;
	x-unix-mode=0644;
	name="v2-0001-doc-Fix-glossary-entry-for-data-checksums-workers.patch"
Content-Transfer-Encoding: quoted-printable

=46rom=20efaefdf09522fe2dfaf63347cd96a8ba341f340c=20Mon=20Sep=2017=20=
00:00:00=202001=0AFrom:=20Daniel=20Gustafsson=20=
<dgustafsson@postgresql.org>=0ADate:=20Thu,=209=20Jul=202026=2010:23:22=20=
+0200=0ASubject:=20[PATCH=20v2=201/2]=20doc:=20Fix=20glossary=20entry=20=
for=20data=20checksums=20workers=0A=0AThe=20glossary=20entry=20for=20=
data=20checksums=20workers=20incorrectly=20stated=20that=0Athey=20were=20=
auxiliary=20processes,=20but=20they=20are=20implementerd=20as=20=
background=0Aworkers.=20=20Fix,=20and=20while=20there,=20simplify=20the=20=
entry=20by=20combining=20the=0Aworker=20and=20launcher=20into=20a=20=
single=20glossary=20term.=0A=0AReported-by:=20Fujii=20Masao=20=
<masao.fujii@gmail.com>=0ADiscussion:=20=
https://postgr.es/m/CAHGQGwEv-C9ia+rBYyePzO8F=3D5FVvS412ZqcOupazuOb5RafNg@=
mail.gmail.com=0A---=0A=20doc/src/sgml/glossary.sgml=20|=2032=20=
++++++++++++--------------------=0A=201=20file=20changed,=2012=20=
insertions(+),=2020=20deletions(-)=0A=0Adiff=20--git=20=
a/doc/src/sgml/glossary.sgml=20b/doc/src/sgml/glossary.sgml=0Aindex=20=
f7f69afc922..9052f8bbf41=20100644=0A---=20a/doc/src/sgml/glossary.sgml=0A=
+++=20b/doc/src/sgml/glossary.sgml=0A@@=20-199,8=20+199,6=20@@=0A=20=20=20=
=20=20=20(but=20not=20the=20autovacuum=20workers),=0A=20=20=20=20=20=20=
the=20<glossterm=20linkend=3D"glossary-background-writer">background=20=
writer</glossterm>,=0A=20=20=20=20=20=20the=20<glossterm=20=
linkend=3D"glossary-checkpointer">checkpointer</glossterm>,=0A-=20=20=20=20=
=20the=20<glossterm=20linkend=3D"glossary-data-checksums-worker">data=20=
checksums=20worker</glossterm>,=0A-=20=20=20=20=20the=20<glossterm=20=
linkend=3D"glossary-data-checksums-worker-launcher">data=20checksums=20=
worker=20launcher</glossterm>,=0A=20=20=20=20=20=20the=20<glossterm=20=
linkend=3D"glossary-logger">logger</glossterm>,=0A=20=20=20=20=20=20the=20=
<glossterm=20linkend=3D"glossary-startup-process">startup=20=
process</glossterm>,=0A=20=20=20=20=20=20the=20<glossterm=20=
linkend=3D"glossary-wal-archiver">WAL=20archiver</glossterm>,=0A@@=20=
-236,8=20+234,9=20@@=0A=20=20=20=20=20=20which=20runs=20system-=20or=20=
user-supplied=20code.=0A=20=20=20=20=20=20Serves=20as=20infrastructure=20=
for=20several=20features=20in=0A=20=20=20=20=20=20=
<productname>PostgreSQL</productname>,=20such=20as=0A-=20=20=20=20=20=
<glossterm=20linkend=3D"glossary-replication">logical=20=
replication</glossterm>=0A-=20=20=20=20=20and=20<glossterm=20=
linkend=3D"glossary-parallel-query">parallel=20queries</glossterm>.=0A+=20=
=20=20=20=20<glossterm=20linkend=3D"glossary-replication">logical=20=
replication</glossterm>,=0A+=20=20=20=20=20<glossterm=20=
linkend=3D"glossary-parallel-query">parallel=20queries</glossterm>=20and=0A=
+=20=20=20=20=20<glossterm=20=
linkend=3D"glossary-data-checksums-process">data=20checksums=20=
processing</glossterm>.=0A=20=20=20=20=20=20In=20addition,=20<glossterm=20=
linkend=3D"glossary-extension">Extensions</glossterm>=20can=20add=0A=20=20=
=20=20=20=20custom=20background=20worker=20processes.=0A=20=20=20=20=
</para>=0A@@=20-588,24=20+587,17=20@@=0A=20=20=20=20<glosssee=20=
otherterm=3D"glossary-data-directory"=20/>=0A=20=20=20</glossentry>=0A=20=
=0A-=20=20<glossentry=20id=3D"glossary-data-checksums-worker">=0A-=20=20=20=
<glossterm>Data=20Checksums=20Worker</glossterm>=0A+=20=20<glossentry=20=
id=3D"glossary-data-checksums-process">=0A+=20=20=20<glossterm>Data=20=
Checksums=20(process)</glossterm>=0A=20=20=20=20<glossdef>=0A=20=20=20=20=
=20<para>=0A-=20=20=20=20=20A=20<glossterm=20=
linkend=3D"glossary-background-worker">background=20worker</glossterm>=0A=
-=20=20=20=20=20which=20enables=20data=20checksums=20in=20a=20specific=20=
database.=0A-=20=20=20=20</para>=0A-=20=20=20</glossdef>=0A-=20=20=
</glossentry>=0A-=0A-=20=20<glossentry=20=
id=3D"glossary-data-checksums-worker-launcher">=0A-=20=20=20=
<glossterm>Data=20Checksums=20Worker=20Launcher</glossterm>=0A-=20=20=20=
<glossdef>=0A-=20=20=20=20<para>=0A-=20=20=20=20=20A=20<glossterm=20=
linkend=3D"glossary-background-worker">background=20worker</glossterm>=0A=
-=20=20=20=20=20which=20starts=20<glossterm=20=
linkend=3D"glossary-data-checksums-worker">=20data=0A-=20=20=20=20=20=
checksum=20worker</glossterm>=20processes=20for=20enabling=20data=20=
checksums=20in=20each=0A-=20=20=20=20=20database,=20or=20disables=20data=20=
checksums=20cluster-wide.=0A+=20=20=20=20=20A=20set=20of=0A+=20=20=20=20=20=
<glossterm=20linkend=3D"glossary-background-worker">background=20=
worker</glossterm>=0A+=20=20=20=20=20processes=20which=20can=20enable=20=
or=20disable=20data=20checksums=20in=20a=20running=20cluster.=0A+=20=20=20=
=20=20The=20process=20which=20coordinates=20the=20work=20is=20known=20as=20=
the=0A+=20=20=20=20=20<firstterm>data=20checksums=20launcher</firstterm>=20=
and=20the=20process=20which=0A+=20=20=20=20=20operate=20on=20the=20=
individual=20databases=20is=20known=20as=20the=0A+=20=20=20=20=20=
<firstterm>data=20checksums=20worker</firstterm>.=0A=20=20=20=20=20=
</para>=0A=20=20=20=20</glossdef>=0A=20=20=20</glossentry>=0A--=20=0A=
2.39.3=20(Apple=20Git-146)=0A=0A=

--Apple-Mail=_D71CB3AD-5BAE-4741-AFCE-8001BABE111C--