On 2021-Aug-14, Justin Pryzby wrote:
> I elaborated on your definition and added here.
> https://commitfest.postgresql.org/34/3285/
Thanks! This works for me. After looking at it, it seemed to me that
listing the autovacuum launcher is perfectly adapted, so we might as
well do it; and add verbiage about it to the autovacuum entry. (I was
first adding a whole new glossary entry for it, but it seemed overkill.)
I also ended up adding an entry for WAL sender -- seems to round things
nicely.
... In doing so I noticed that the definition for startup process and
WAL receiver is slightly wrong. WAL receiver only receives, it doesn't
replay; it is always the startup process the one that replays. So I
changed that too.
What do you think?
PS: I almost want to add a note to the startup process entry, something
like "(The name is historical: it refers to its task before the
introduction of replication, when it was only related to the server
starting up after a crash.)"
PPS: Do we want the list to be in alphabetical order, or some other
order?
--
Álvaro Herrera 39°49'30"S 73°17'W — https://www.EnterpriseDB.com/
"Tiene valor aquel que admite que es un cobarde" (Fernandel)
>From 5057123f814625ef4fae6e75ff3d67b390615b4f Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryz...@telsasoft.com>
Date: Sat, 14 Aug 2021 18:51:37 -0500
Subject: [PATCH v2] glossary definitions for auxiliary processes
---
doc/src/sgml/glossary.sgml | 80 +++++++++++++++++++++++++++++++++++---
1 file changed, 74 insertions(+), 6 deletions(-)
diff --git a/doc/src/sgml/glossary.sgml b/doc/src/sgml/glossary.sgml
index 63ff4bbdf0..b311293492 100644
--- a/doc/src/sgml/glossary.sgml
+++ b/doc/src/sgml/glossary.sgml
@@ -114,7 +114,11 @@
A set of background processes that routinely perform
<glossterm linkend="glossary-vacuum">vacuum</glossterm>
and <glossterm linkend="glossary-analyze">analyze</glossterm>
- operations.
+ operations. The auxiliary process that coordinates the work
+ and is always present (unless autovacuum is disabled)
+ is known as the <firstterm>autovacuum launcher</firstterm>,
+ and the processes that carry out the tasks are known as the
+ <firstterm>autovacuum workers</firstterm>.
</para>
<para>
For more information, see
@@ -123,6 +127,28 @@
</glossdef>
</glossentry>
+ <glossentry id="glossary-auxiliary-proc">
+ <glossterm>Auxiliary process</glossterm>
+ <glossdef>
+ <para>
+ A process that is in charge of some specific background task for
+ an <glossterm linkend="glossary-instance">instance</glossterm>.
+ The auxiliary processes consist of
+ the <glossterm linkend="glossary-background-writer">background writer</glossterm>,
+ the <glossterm linkend="glossary-checkpointer">checkpointer</glossterm>,
+ the <glossterm linkend="glossary-stats-collector">statistics collector</glossterm>,
+ the <glossterm linkend="glossary-logger">logger</glossterm>,
+ the <glossterm linkend="glossary-startup-process">startup process</glossterm>,
+ the <glossterm linkend="glossary-autovacuum">autovacuum launcher</glossterm>
+ (but not the autovacuum workers),
+ the <glossterm linkend="glossary-wal-archiver">WAL archiver</glossterm>,
+ the <glossterm linkend="glossary-wal-receiver">WAL receiver</glossterm>
+ (but not the <glossterm linkend="glossary-wal-sender">WAL senders</glossterm>),
+ and the <glossterm linkend="glossary-wal-writer">WAL writer</glossterm>.
+ </para>
+ </glossdef>
+ </glossentry>
+
<glossentry id="glossary-backend">
<glossterm>Backend (process)</glossterm>
<glossdef>
@@ -163,7 +189,7 @@
<glossterm>Background writer (process)</glossterm>
<glossdef>
<para>
- A process that writes dirty
+ An auxiliary process that writes dirty
<glossterm linkend="glossary-data-page">data pages</glossterm> from
<glossterm linkend="glossary-shared-memory">shared memory</glossterm> to
the file system. It wakes up periodically, but works only for a short
@@ -285,7 +311,7 @@
<glossterm>Checkpointer (process)</glossterm>
<glossdef>
<para>
- A specialized process responsible for executing checkpoints.
+ An auxiliary process that is responsible for executing checkpoints.
</para>
</glossdef>
</glossentry>
@@ -881,7 +907,7 @@
<glossterm>Logger (process)</glossterm>
<glossdef>
<para>
- If activated, the process
+ An auxiliary process which (if enabled)
writes information about database events into the current
<glossterm linkend="glossary-log-file">log file</glossterm>.
When reaching certain time- or
@@ -1452,6 +1478,16 @@
</glossdef>
</glossentry>
+ <glossentry id="glossary-startup-process">
+ <glossterm>Startup process</glossterm>
+ <glossdef>
+ <para>
+ An auxiliary process that replays WAL during replication and
+ crash recovery.
+ </para>
+ </glossdef>
+ </glossentry>
+
<glossentry id="glossary-sql-object">
<glossterm>SQL object</glossterm>
<glossdef>
@@ -1514,7 +1550,7 @@
<glossterm>Stats collector (process)</glossterm>
<glossdef>
<para>
- This process collects statistical information about the
+ An auxiliary process that collects statistical information about the
<glossterm linkend="glossary-instance">instance</glossterm>'s activities.
</para>
<para>
@@ -1856,7 +1892,8 @@
<glossterm>WAL archiver (process)</glossterm>
<glossdef>
<para>
- A process that saves copies of <glossterm linkend="glossary-wal-file">WAL files</glossterm>
+ An auxiliary process that saves copies of
+ <glossterm linkend="glossary-wal-file">WAL files</glossterm>
for the purpose of creating backups or keeping
<glossterm linkend="glossary-replica">replicas</glossterm> current.
</para>
@@ -1914,11 +1951,42 @@
</glossdef>
</glossentry>
+ <glossentry id="glossary-wal-receiver">
+ <glossterm>WAL receiver</glossterm>
+ <glossdef>
+ <para>
+ An auxiliary process that runs on a
+ <glossterm linkend="glossary-replica">replica</glossterm>
+ to receive WAL from the primary server for replay by the
+ <glossterm linkend="glossary-startup-process">startup process</glossterm>.
+ </para>
+
+ <para>
+ For more information, see
+ <xref linkend="warm-standby"/>.
+ </para>
+ </glossdef>
+ </glossentry>
+
<glossentry>
<glossterm>WAL segment</glossterm>
<glosssee otherterm="glossary-wal-file" />
</glossentry>
+ <glossentry id="glossary-wal-sender">
+ <glossterm>WAL sender (process)</glossterm>
+ <glossdef>
+ <para>
+ A process that runs on a server that streams WAL over a
+ network. The receiving end can be a
+ <glossterm linkend="glossary-wal-receiver">WAL receiver</glossterm>
+ in a <glossterm linkend="glossary-replica">replica</glossterm>,
+ <xref linkend="app-pgreceivewal"/>, or any other client program
+ that speaks the replication protocol.
+ </para>
+ </glossdef>
+ </glossentry>
+
<glossentry id="glossary-wal-writer">
<glossterm>WAL writer (process)</glossterm>
<glossdef>
--
2.30.2
