From: Justin Pryzby <pryzbyj@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


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