Re: Add A Glossary

From 6cdbfd1d9f2d6c7fa815aab853a51f86b3650e11 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Fri, 15 May 2020 13:04:11 -0400
Subject: [PATCH v3] Review of the glossary
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Add some more terms, clarify some definitions, remove redundant terms,
move a couple of terms to keep alphabetical order.

Co-authored-by: Jürgen Purtz <juergen@purtz.de>
Co-authored-by: Erik Rijkers <er@xs4all.nl>
Co-authored-by: Laurenz Albe <laurenz.albe@cybertec.at>
Discussion: https://postgr.es/m/7b9b469e804777ac9df4d37716db935e@xs4all.nl
---
 doc/src/sgml/acronyms.sgml |   2 +-
 doc/src/sgml/glossary.sgml | 536 ++++++++++++++++++++++---------------
 2 files changed, 316 insertions(+), 222 deletions(-)

diff --git a/doc/src/sgml/acronyms.sgml b/doc/src/sgml/acronyms.sgml
index f638665dc9..b05c065546 100644
--- a/doc/src/sgml/acronyms.sgml
+++ b/doc/src/sgml/acronyms.sgml
@@ -766,7 +766,7 @@
     <term><acronym>XID</acronym></term>
     <listitem>
      <para>
-      <link linkend="datatype-oid">Transaction Identifier</link>
+      <glossterm linkend="glossary-xid">Transaction identifier</glossterm>
      </para>
     </listitem>
    </varlistentry>
diff --git a/doc/src/sgml/glossary.sgml b/doc/src/sgml/glossary.sgml
index 8c6cb6e942..a1e8a595c8 100644
--- a/doc/src/sgml/glossary.sgml
+++ b/doc/src/sgml/glossary.sgml
@@ -7,8 +7,23 @@
  </para>
 
  <glosslist>
+  <glossentry id="glossary-acid">
+   <glossterm>ACID</glossterm>
+   <glossdef>
+    <para>
+     <glossterm linkend="glossary-atomicity">Atomicity</glossterm>,
+     <glossterm linkend="glossary-consistency">Consistency</glossterm>,
+     <glossterm linkend="glossary-isolation">Isolation</glossterm>, and
+     <glossterm linkend="glossary-durability">Durability</glossterm>.
+     This set of properties of database transactions is intended to
+     guarantee validity in concurrent operation and even in event of
+     errors, power failures, etc.
+    </para>     
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-aggregate">
-   <glossterm>Aggregate Function</glossterm>
+   <glossterm>Aggregate function</glossterm>
    <glossdef>
     <para>
      A <glossterm linkend="glossary-function">function</glossterm> that
@@ -35,11 +50,15 @@
      to make decisions about how to execute
      <glossterm linkend="glossary-query">queries</glossterm>.
     </para>
+    <para>
+     (Don't confuse this term with the <literal>ANALYZE</literal> option
+     to the <xref linkend="sql-explain"/> command.)
+    </para>
    </glossdef>
   </glossentry>
 
   <glossentry>
-   <glossterm>Analytic Function</glossterm>
+   <glossterm>Analytic function</glossterm>
    <glosssee otherterm="glossary-window-function" />
   </glossentry>
 
@@ -106,8 +125,8 @@
    <glossdef>
     <para>
      Process of an <glossterm linkend="glossary-instance">instance</glossterm>
-     which act on behalf of <glossterm linkend="glossary-session">client sessions</glossterm>
-     and handle their requests.
+     which acts on behalf of a <glossterm linkend="glossary-session">client session</glossterm>
+     and handles its requests.
     </para>
     <para>
      (Don't confuse this term with the similar terms
@@ -118,7 +137,7 @@
   </glossentry>
 
   <glossentry id="glossary-background-worker">
-   <glossterm>Background Worker (process)</glossterm>
+   <glossterm>Background worker (process)</glossterm>
    <glossdef>
     <para>
      Process within an <glossterm linkend="glossary-instance">instance</glossterm>,
@@ -138,10 +157,11 @@
   </glossentry>
 
   <glossentry id="glossary-background-writer">
-   <glossterm>Background Writer (process)</glossterm>
+   <glossterm>Background writer (process)</glossterm>
    <glossdef>
     <para>
-     A process that continuously writes dirty pages from
+     A 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
      period in order to distribute its expensive <acronym>I/O</acronym>
@@ -155,6 +175,16 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-bloat">
+   <glossterm>Bloat</glossterm>
+   <glossdef>
+    <para>
+     Space in data pages which does not contain current row versions,
+     such as unused (free) space or outdated row versions.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-cast">
    <glossterm>Cast</glossterm>
    <glossdef>
@@ -190,7 +220,7 @@
   </glossentry>
 
   <glossentry id="glossary-check-constraint">
-   <glossterm>Check Constraint</glossterm>
+   <glossterm>Check constraint</glossterm>
    <glossdef>
     <para>
      A type of <glossterm linkend="glossary-constraint">constraint</glossterm>
@@ -208,15 +238,6 @@
    </glossdef>
   </glossentry>
 
-  <glossentry id="glossary-checkpointer">
-   <glossterm>Checkpointer (process)</glossterm>
-   <glossdef>
-    <para>
-     A specialized process responsible for executing checkpoints.
-    </para>
-   </glossdef>
-  </glossentry>
-
   <glossentry id="glossary-checkpoint">
    <glossterm>Checkpoint</glossterm>
    <glossdef>
@@ -244,6 +265,15 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-checkpointer">
+   <glossterm>Checkpointer (process)</glossterm>
+   <glossdef>
+    <para>
+     A specialized process responsible for executing checkpoints.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry>
    <glossterm>Class (archaic)</glossterm>
    <glosssee otherterm="glossary-relation" />
@@ -262,27 +292,6 @@
    </glossdef>
   </glossentry>
 
-  <glossentry id="glossary-cluster">
-   <glossterm>Cluster</glossterm>
-   <glossdef>
-    <para>
-     A group of <glossterm linkend="glossary-database">databases</glossterm> plus their
-     <glossterm linkend="glossary-global-sql-object">global SQL objects</glossterm>. The
-     <firstterm>cluster</firstterm> is managed by exactly one
-     <glossterm linkend="glossary-instance">instance</glossterm>. A newly created
-     Cluster will have three databases created automatically. They are
-     <literal>template0</literal>, <literal>template1</literal>, and
-     <literal>postgres</literal>. It is expected that an application will
-     create one or more additional database aside from these three.
-    </para>
-    <para>
-     (Don't confuse the <productname>PostgreSQL</productname>-specific term
-     <glossterm linkend="glossary-cluster">Cluster</glossterm> with the SQL
-     command <command>CLUSTER</command>).
-    </para>
-   </glossdef>
-  </glossentry>
-
   <glossentry id="glossary-column">
    <glossterm>Column</glossterm>
    <glossdef>
@@ -363,7 +372,10 @@
    <glossdef>
     <para>
      A restriction on the values of data allowed within a
-     <glossterm linkend="glossary-table">Table</glossterm>.
+     <glossterm linkend="glossary-table">table</glossterm>,
+     or in attributes of a
+     <!-- XXX Should have term "domain". Need term "type" for that. -->
+     <firstterm>domain</firstterm>.
     </para>
     <para>
      For more information, see
@@ -373,19 +385,19 @@
   </glossentry>
 
   <glossentry>
-   <glossterm>Data Area</glossterm>
+   <glossterm>Data area</glossterm>
    <glosssee otherterm="glossary-data-directory" />
   </glossentry>
 
   <glossentry id="glossary-data-directory">
-   <glossterm>Data Directory</glossterm>
+   <glossterm>Data directory</glossterm>
    <glossdef>
     <para>
      The base directory on the filesystem of a
      <glossterm linkend="glossary-server">server</glossterm> that contains all
-     data files and subdirectories associated with a
-     <glossterm linkend="glossary-cluster">cluster</glossterm> with the
-     exception of <glossterm linkend="glossary-tablespace">tablespaces</glossterm>.
+     data files and subdirectories associated with an
+     <glossterm linkend="glossary-instance">instance</glossterm> (with the
+     exception of <glossterm linkend="glossary-tablespace">tablespaces</glossterm>).
      The environment variable <literal>PGDATA</literal> is commonly used to
      refer to the
      <glossterm linkend="glossary-data-directory">data directory</glossterm>.
@@ -416,15 +428,31 @@
   </glossentry>
 
   <glossentry>
-   <glossterm>Database Server</glossterm>
+   <glossterm>Database server</glossterm>
    <glosssee otherterm="glossary-instance" />
   </glossentry>
 
+  <glossentry id="glossary-data-page">
+   <glossterm>Data page</glossterm>
+   <glossdef>
+    <para>
+     The basic structure used to store relation data.
+     All pages are of the same size.
+     Data pages are typically stored on disk, each in a specific file,
+     and can be read to <glossterm linkend="glossary-shared-memory">shared buffers</glossterm>
+     where they can be modified, becoming
+     <firstterm>dirty</firstterm>.  They become clean when written
+     to disk.  New pages, which initially exist in memory only, are also
+     dirty until written.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-datum">
    <glossterm>Datum</glossterm>
    <glossdef>
     <para>
-     The internal representation of one value of a <acronym>SQL</acronym>
+     The internal representation of one value of an <acronym>SQL</acronym>
      data type.
     </para>
    </glossdef>
@@ -434,7 +462,7 @@
    <glossterm>Delete</glossterm>
    <glossdef>
     <para>
-     A <acronym>SQL</acronym> command which removes
+     An <acronym>SQL</acronym> command which removes
      <glossterm linkend="glossary-tuple">rows</glossterm> from a given
      <glossterm linkend="glossary-table">table</glossterm>
      or <glossterm linkend="glossary-relation">relation</glossterm>.
@@ -459,6 +487,11 @@
    </glossdef>
   </glossentry>
 
+  <glossentry>
+   <glossterm>Epoch</glossterm>
+   <glosssee otherterm="glossary-xid" />
+  </glossentry>
+
   <glossentry id="glossary-extension">
    <glossterm>Extension</glossterm>
    <glossdef>
@@ -475,12 +508,13 @@
   </glossentry>
 
   <glossentry id="glossary-file-segment">
-   <glossterm>File Segment</glossterm>
+   <glossterm>File segment</glossterm>
    <glossdef>
     <para>
      A physical file which stores data for a given
      <glossterm linkend="glossary-relation">relation</glossterm>.
-     File segments are limited in size by a configuration value,
+     File segments are limited in size by a configuration value
+     (typically 1 gigabyte),
      so if a relation exceeds that size, it is split into multiple segments.
     </para>
     <para>
@@ -495,14 +529,14 @@
   </glossentry>
 
   <glossentry id="glossary-foreign-data-wrapper">
-   <glossterm>Foreign Data Wrapper</glossterm>
+   <glossterm>Foreign data wrapper</glossterm>
    <glossdef>
     <para>
      A means of representing data that is not contained in the local
      <glossterm linkend="glossary-database">database</glossterm> so that it appears as if were in local
-     <glossterm linkend="glossary-table">table(s)</glossterm>. With a Foreign Data Wrapper it is
+     <glossterm linkend="glossary-table">table(s)</glossterm>. With a foreign data wrapper it is
      possible to define a <glossterm linkend="glossary-foreign-server">foreign server</glossterm> and
-     <glossterm linkend="glossary-foreign-table">foreign table</glossterm>s.
+     <glossterm linkend="glossary-foreign-table">foreign tables</glossterm>.
     </para>
     <para>
      For more information, see
@@ -512,7 +546,7 @@
   </glossentry>
 
   <glossentry id="glossary-foreign-key">
-   <glossterm>Foreign Key</glossterm>
+   <glossterm>Foreign key</glossterm>
    <glossdef>
     <para>
      A type of <glossterm linkend="glossary-constraint">constraint</glossterm>
@@ -527,7 +561,7 @@
   </glossentry>
 
   <glossentry id="glossary-foreign-server">
-   <glossterm>Foreign Server</glossterm>
+   <glossterm>Foreign server</glossterm>
    <glossdef>
     <para>
      A named collection of
@@ -544,7 +578,7 @@
   </glossentry>
 
   <glossentry id="glossary-foreign-table">
-   <glossterm>Foreign Table</glossterm>
+   <glossterm>Foreign table</glossterm>
    <glossdef>
     <para>
      A <glossterm linkend="glossary-relation">relation</glossterm> which appears to have
@@ -564,6 +598,38 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-fork">
+   <glossterm>Fork</glossterm>
+   <glossdef>
+    <para>
+     Each of the separate segmented file sets in which a relation is stored.
+     The <firstterm>main fork</firstterm> is where the actual data resides.
+     There also exist two secondary forks for metadata:
+     the <glossterm linkend="glossary-fsm">free space map</glossterm>
+     and the <glossterm linkend="glossary-vm">visibility map</glossterm>.
+     <glossterm linkend="glossary-unlogged">Unlogged relations</glossterm>
+     also have an <firstterm>init fork</firstterm>.
+    </para>
+   </glossdef>
+  </glossentry>
+
+  <glossentry id="glossary-fsm">
+   <glossterm>Free space map (fork)</glossterm>
+   <glossdef>
+    <para>
+     A storage structure that keeps metadata about each data page of a table's
+     main fork.  The free space map entry for each page stores the
+     amount of free space that's available for future tuples, and is structured
+     to be efficiently searched for available space for a new tuple of a given
+     size.
+    </para>
+    <para>
+     For more information, see
+     <xref linkend="storage-fsm"/>.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-function">
    <glossterm>Function</glossterm>
    <glossdef>
@@ -579,28 +645,11 @@
    </glossdef>
   </glossentry>
 
-  <glossentry id="glossary-global-sql-object">
-   <glossterm>Global SQL Object</glossterm>
-   <glossdef>
-    <para>
-     <glossterm linkend="glossary-sql-object">SQL objects</glossterm> which do
-     not belong to a specific
-     <glossterm linkend="glossary-database">database</glossterm>.
-    </para>
-    <para>
-     These objects are
-     <glossterm linkend="glossary-role">roles</glossterm>,
-     <glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
-     replication origins, and subscriptions for logical replication.
-    </para>
-   </glossdef>
-  </glossentry>
-
   <glossentry id="glossary-grant">
    <glossterm>Grant</glossterm>
    <glossdef>
     <para>
-     A <acronym>SQL</acronym> command that is used to allow
+     An <acronym>SQL</acronym> command that is used to allow
      <glossterm linkend="glossary-user">users</glossterm> or
      <glossterm linkend="glossary-role">role</glossterm> to access
      specific objects within the <glossterm linkend="glossary-database">database</glossterm>.
@@ -619,8 +668,9 @@
      Contains the values of <glossterm linkend="glossary-tuple">row</glossterm>
      attributes (i.e. the data) for a
      <glossterm linkend="glossary-relation">relation</glossterm>.
-     The heap is realized within
-     <glossterm linkend="glossary-file-segment">segment files</glossterm>.
+     The heap is realized within one of more
+     <glossterm linkend="glossary-file-segment">file segments</glossterm>
+     in the relation's <glossterm linkend="glossary-fork">main fork</glossterm>.
     </para>
    </glossdef>
   </glossentry>
@@ -629,10 +679,11 @@
    <glossterm>Host</glossterm>
    <glossdef>
     <para>
-     A computer that communicates with other hosts over a network.
-     This term can be used to refer to either a
-     <glossterm linkend="glossary-client">client</glossterm>
-     or a <glossterm linkend="glossary-server">server</glossterm>.
+     A computer that communicates with other computers over a network.
+     This is sometimes used as a synonym for
+     <glossterm linkend="glossary-server">server</glossterm>.
+     It is also used to refer to a computer where
+     <glossterm linkend="glossary-client">client processes</glossterm> run.
     </para>
    </glossdef>
   </glossentry>
@@ -659,7 +710,7 @@
    <glossterm>Insert</glossterm>
    <glossdef>
     <para>
-     A <acronym>SQL</acronym> command used to add new data into a
+     An <acronym>SQL</acronym> command used to add new data into a
      <glossterm linkend="glossary-table">table</glossterm>.
     </para>
     <para>
@@ -673,27 +724,28 @@
    <glossterm>Instance</glossterm>
    <glossdef>
     <para>
-     An <glossterm>instance</glossterm> is a group of processes,
-     its supporting <glossterm linkend="glossary-data-directory">storage space</glossterm>,
-     plus their
-     common <glossterm linkend="glossary-shared-memory">shared memory</glossterm>,
-     running on a single <glossterm linkend="glossary-server">server</glossterm>.
-     The <glossterm linkend="glossary-instance">instance</glossterm>
-     handles all key features of a <acronym>DBMS</acronym>: read and write
-     access to files and shared memory, assurance of
-     the <acronym>ACID</acronym> paradigm, <acronym>MVCC</acronym>,
-     <glossterm linkend="glossary-connection">connections</glossterm> to client programs, backup,
-     recovery, replication, privileges, etc.
+     A set of databases and accompanying global SQL objects that are stored in
+     the same <glossterm linkend="glossary-data-directory">data directory</glossterm>
+     in a single <glossterm linkend="glossary-server">server</glossterm>.
+     If running, one
+     <glossterm linkend="glossary-postmaster">postmaster process</glossterm>
+     manages a group of backend and auxiliary processes that communicate
+     using a common <glossterm linkend="glossary-shared-memory">shared memory</glossterm>
+     area.  Many instances can run on the same
+     <glossterm linkend="glossary-server">server</glossterm>
+     as long as their <acronym>TCP</acronym> ports do not conflict.
     </para>
     <para>
-     An <glossterm>instance</glossterm> manages exactly one
-     <glossterm linkend="glossary-cluster">cluster</glossterm>.
+     The instance handles all key features of a <acronym>DBMS</acronym>:
+     read and write access to files and shared memory,
+     assurance of the <acronym>ACID</acronym> properties,
+     <glossterm linkend="glossary-connection">connections</glossterm> to client processes,
+     privilege verification, crash recovery, replication, etc.
     </para>
     <para>
-     Many <glossterm>instances</glossterm> can run on the same server as
-     long as their <acronym>TCP/IP</acronym> ports do not conflict.
-     Different instances on a server may use the
-     same or different versions of <productname>PostgreSQL</productname>.
+     In <productname>PostgreSQL</productname>, the term
+     <firstterm>cluster</firstterm> is also sometimes used to refer to an instance.
+     (Don't confuse this term with the SQL command <command>CLUSTER</command>.)
     </para>
    </glossdef>
   </glossentry>
@@ -717,7 +769,7 @@
    <glossterm>Join</glossterm>
    <glossdef>
     <para>
-     A <acronym>SQL</acronym> keyword used in <command>SELECT</command> statements for
+     An <acronym>SQL</acronym> keyword used in <command>SELECT</command> statements for
      combining data from multiple <glossterm linkend="glossary-relation">relations</glossterm>.
     </para>
    </glossdef>
@@ -748,7 +800,7 @@
   </glossentry>
 
   <glossentry id="glossary-log-file">
-   <glossterm>Log File</glossterm>
+   <glossterm>Log file</glossterm>
    <glossdef>
     <para>
      Log files contain human-readable text lines about events.
@@ -761,6 +813,29 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-log-record">
+   <glossterm>Log record</glossterm>
+    <glossdef>
+     <para>
+      Archaic term for a <glossterm linkend="glossary-wal-record">WAL record</glossterm>.
+     </para>
+    </glossdef>
+  </glossentry>
+
+  <glossentry id="glossary-logged">
+   <glossterm>Logged</glossterm>
+   <glossdef>
+    <para>
+     A <glossterm linkend="glossary-table">table</glossterm> is considered
+     <glossterm linkend="glossary-logged">logged</glossterm> if changes to it are sent to the
+     <glossterm linkend="glossary-wal">WAL</glossterm>. By default, all regular
+     tables are logged. A table can be specified as
+     <glossterm linkend="glossary-unlogged">unlogged</glossterm> either at
+     creation time or via the <command>ALTER TABLE</command> command.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-logger">
    <glossterm>Logger (process)</glossterm>
    <glossdef>
@@ -780,29 +855,6 @@
    </glossdef>
   </glossentry>
 
-  <glossentry id="glossary-log-record">
-   <glossterm>Log Record</glossterm>
-    <glossdef>
-     <para>
-      Archaic term for a <glossterm linkend="glossary-wal-record">WAL record</glossterm>.
-     </para>
-    </glossdef>
-  </glossentry>
-
-  <glossentry id="glossary-logged">
-   <glossterm>Logged</glossterm>
-   <glossdef>
-    <para>
-     A <glossterm linkend="glossary-table">table</glossterm> is considered
-     <glossterm linkend="glossary-logged">logged</glossterm> if changes to it are sent to the
-     <glossterm linkend="glossary-wal">WAL</glossterm>. By default, all regular
-     tables are logged. A table can be specified as
-     <glossterm linkend="glossary-unlogged">unlogged</glossterm> either at
-     creation time or via the <command>ALTER TABLE</command> command.
-    </para>
-   </glossdef>
-  </glossentry>
-
   <glossentry>
    <glossterm>Master (server)</glossterm>
    <glosssee otherterm="glossary-primary-server" />
@@ -831,7 +883,7 @@
   </glossentry>
 
   <glossentry id="glossary-materialized-view">
-   <glossterm>Materialized View</glossterm>
+   <glossterm>Materialized view</glossterm>
    <glossdef>
     <para>
      A <glossterm linkend="glossary-relation">relation</glossterm> that is
@@ -869,8 +921,8 @@
    <glossterm>Null</glossterm>
    <glossdef>
     <para>
-     A concept of non-existence that is a central tenet of Relational
-     Database Theory. It represents the absence of value.
+     A concept of non-existence that is a central tenet of relational
+     database theory. It represents the absence of a definite value.
     </para>
    </glossdef>
   </glossentry>
@@ -881,7 +933,7 @@
   </glossentry>
 
   <glossentry id="glossary-parallel-query">
-   <glossterm>Parallel Query</glossterm>
+   <glossterm>Parallel query</glossterm>
    <glossdef>
     <para>
      The ability to handle parts of executing a
@@ -918,7 +970,7 @@
   </glossentry>
 
   <glossentry id="glossary-partitioned-table">
-   <glossterm>Partitioned Table</glossterm>
+   <glossterm>Partitioned table</glossterm>
    <glossdef>
     <para>
      A <glossterm linkend="glossary-relation">relation</glossterm> that is
@@ -960,7 +1012,7 @@
   </glossentry>
 
   <glossentry id="glossary-primary-key">
-   <glossterm>Primary Key</glossterm>
+   <glossterm>Primary key</glossterm>
    <glossdef>
     <para>
      A special case of a
@@ -1011,7 +1063,7 @@
   </glossentry>
 
   <glossentry id="glossary-planner">
-   <glossterm>Query Planner</glossterm>
+   <glossterm>Query planner</glossterm>
    <glossdef>
     <para>
      The part of <productname>PostgreSQL</productname> that is devoted to
@@ -1034,7 +1086,7 @@
   </glossentry>
 
   <glossentry id="glossary-referential-integrity">
-   <glossterm>Referential Integrity</glossterm>
+   <glossterm>Referential integrity</glossterm>
    <glossdef>
     <para>
      A means of restricting data in one <glossterm linkend="glossary-relation">relation</glossterm>
@@ -1055,9 +1107,11 @@
      <glossterm linkend="glossary-attribute">attributes</glossterm>
      defined in a specific order.
      <glossterm linkend="glossary-table">Tables</glossterm>,
+     <glossterm linkend="glossary-sequence">sequences</glossterm>,
      <glossterm linkend="glossary-view">views</glossterm>,
      <glossterm linkend="glossary-foreign-table">foreign tables</glossterm>,
-     <glossterm linkend="glossary-materialized-view">materialized views</glossterm>, and
+     <glossterm linkend="glossary-materialized-view">materialized views</glossterm>,
+     composite types, and
      <glossterm linkend="glossary-index">indexes</glossterm> are all relations.
     </para>
     <para>
@@ -1068,7 +1122,7 @@
   </glossentry>
 
   <glossentry id="glossary-replica">
-   <glossterm>Replica</glossterm>
+   <glossterm>Replica (server)</glossterm>
    <glossdef>
     <para>
      A <glossterm linkend="glossary-database">database</glossterm> that is paired
@@ -1098,12 +1152,13 @@
   </glossentry>
 
   <glossentry id="glossary-result-set">
-   <glossterm>Result Set</glossterm>
+   <glossterm>Result set</glossterm>
    <glossdef>
     <para>
      A data structure transmitted from a
      <glossterm linkend="glossary-backend">backend process</glossterm> to
-     client program upon the completion of a <acronym>SQL</acronym>
+     a <glossterm linkend="glossary-client">client</glossterm> upon the
+     completion of an <acronym>SQL</acronym>
      command, usually a <command>SELECT</command> but it can be an
      <command>INSERT</command>, <command>UPDATE</command>, or
      <command>DELETE</command> command if the <literal>RETURNING</literal>
@@ -1135,7 +1190,7 @@
     <para>
      A collection of access privileges to the
      <glossterm linkend="glossary-database">instance</glossterm>.
-     Roless are themselves a privilege that can be granted to other roles.
+     Roles are themselves a privilege that can be granted to other roles.
      This is often done for convenience or to ensure completeness
      when multiple <glossterm linkend="glossary-user">users</glossterm> need
      the same privileges.
@@ -1170,7 +1225,7 @@
    <glossterm>Savepoint</glossterm>
    <glossdef>
     <para>
-     A special mark inside the sequence of steps in a
+     A special mark in the sequence of steps in a
      <glossterm linkend="glossary-transaction">transaction</glossterm>.
      Data modifications after this point in time may be reverted
      to the time of the savepoint.
@@ -1186,13 +1241,15 @@
    <glossterm>Schema</glossterm>
    <glossdef>
     <para>
-     A schema is a namespace for <glossterm linkend="glossary-sql-object">SQL objects</glossterm>,
+     A schema is a namespace for
+     <glossterm linkend="glossary-sql-object">SQL objects</glossterm>,
      which all reside in the same
-     <glossterm linkend="glossary-database">database</glossterm>.  Each
-     SQL object must reside in exactly one schema.
+     <glossterm linkend="glossary-database">database</glossterm>.
+     Each SQL object must reside in exactly one schema.
     </para>
     <para>
-     The names of SQL objects of the same type in the same schema are enforced unique.
+     The names of SQL objects of the same type in the same schema are enforced
+     to be unique.
      There is no restriction on reusing a name in multiple schemas.
     </para>
     <para>
@@ -1205,7 +1262,7 @@
    </glossdef>
    <glossdef>
     <para>
-     More generically, the term <firstterm>Schema</firstterm> is used to mean
+     More generically, the term <firstterm>schema</firstterm> is used to mean
      all data descriptions (<glossterm linkend="glossary-table">table</glossterm> definitions,
      <glossterm linkend="glossary-constraint">constraints</glossterm>, comments, etc)
      for a given <glossterm linkend="glossary-database">database</glossterm> or
@@ -1264,7 +1321,10 @@
      A computer on which <productname>PostgreSQL</productname>
      <glossterm linkend="glossary-instance">instances</glossterm> run.
      The term <firstterm>server</firstterm> denotes real hardware, a
-     container, or a Virtual Machine.
+     container, or a <firstterm>virtual machine</firstterm>.
+    </para>
+    <para>
+     This term is sometimes used to refer to an instance or to a host.
     </para>
    </glossdef>
   </glossentry>
@@ -1279,45 +1339,21 @@
    </glossdef>
   </glossentry>
 
-<!-- XXX we should have a much more concise definition
   <glossentry id="glossary-sequence">
    <glossterm>Sequence</glossterm>
    <glossdef>
     <para>
-     A <glossterm linkend="glossary-database">Database</glossterm> object which
-     represents the mathematical concept of a numerical integral sequence.
-     It can be thought of as a <glossterm linkend="glossary-table">Table</glossterm>
-     with exactly one <glossterm linkend="glossary-tuple">Row</glossterm> and
-     one <glossterm linkend="glossary-column">Column</glossterm>. The
-     value stored is known as the current value. A
-     <glossterm linkend="glossary-sequence">Sequence</glossterm> has a defined
-     direction (usually increasing) and an interval step (usually 1).
-     Whenever the <literal>NEXTVAL</literal> pseudo-column of a
-     <glossterm linkend="glossary-sequence">Sequence</glossterm> is accessed,
-     the current value is moved in the defined direction by the defined
-     interval step, that value is returned to the invoking query,
-     and the current value of the sequence is updated to reflect the new value.
-     The value can be updated multiple times in a single query,
-     the net effect being that each row selected will have a different value.
-     Values taken from a
-     <glossterm linkend="glossary-sequence">Sequence</glossterm> are never
-     reverted, even in the case of a
-     <glossterm linkend="glossary-rollback">Rollback</glossterm>, which means
-     that the <glossterm linkend="glossary-sequence">Sequence</glossterm>
-     will never generate the same number twice, which makes it useful for
-     generating
-     <glossterm linkend="glossary-primary-key">Primary Key</glossterm> values.
-    </para>
-    <para>
-     For more information, see
-     <xref linkend="sql-createsequence"/>.
+     A type of relation that is used to generate values.
+     Typically the generated values are sequential non-repeating numbers.
+     They are commonly used to generate surrogate
+     <glossterm linkend="glossary-primary-key">primary key</glossterm>
+     values.
     </para>
    </glossdef>
   </glossentry>
--->
 
   <glossentry id="glossary-shared-memory">
-   <glossterm>Shared Memory</glossterm>
+   <glossterm>Shared memory</glossterm>
    <glossdef>
     <para>
      <acronym>RAM</acronym> which is used by the processes common to an
@@ -1342,28 +1378,32 @@
    </glossdef>
   </glossentry>
 
+  <glossentry>
+   <glossterm>Standby (server)</glossterm>
+   <glosssee otherterm="glossary-replica" />
+  </glossentry>
+
   <glossentry id="glossary-sql-object">
    <glossterm>SQL Object</glossterm>
     <glossdef>
      <para>
-      A <glossterm linkend="glossary-table">table</glossterm>,
-      <glossterm linkend="glossary-view">view</glossterm>,
-      <glossterm linkend="glossary-materialized-view">materialized view</glossterm>,
-      <glossterm linkend="glossary-index">index</glossterm>,
-      <glossterm linkend="glossary-constraint">constraint</glossterm>,
-<!-- XXX define sequence <glossterm linkend="glossary-sequence"> --> sequence,
-      <glossterm linkend="glossary-function">function</glossterm>,
-      <glossterm linkend="glossary-procedure">procedure</glossterm>,
-      <glossterm linkend="glossary-trigger">trigger</glossterm>,
-      data type, or operator. Every one of those SQL objects
-      belong to exactly one <glossterm linkend="glossary-schema">Schema</glossterm>.
-    </para>
-    <para>
-     There also exist SQL objects that do not belong to schemas; those include
-     <glossterm linkend="glossary-extension">extensions</glossterm>,
-     <glossterm linkend="glossary-cast">data type cases</glossterm>,
-     and
-     <glossterm linkend="glossary-foreign-data-wrapper">foreign data wrappers</glossterm>.
+      Any object that can be created with a <command>CREATE</command>
+      command.  Most objects are specific to one database, and are commonly
+      known as <firstterm>local objects</firstterm>.
+      <glossterm linkend="glossary-role">Roles</glossterm>,
+      <glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
+      replication origins, subscriptions for logical replication, and
+      databases themselves are not local SQL objects since they exist
+      entirely outside of any specific database;
+      they are called <firstterm>global objects</firstterm>.
+     </para>
+     <para>
+      Most local objects belong to a specific
+      <glossterm linkend="glossary-schema">schema</glossterm> in their containing database.
+      There also exist local objects that do not belong to schemas; some examples are
+      <glossterm linkend="glossary-extension">extensions</glossterm>,
+      <glossterm linkend="glossary-cast">data type casts</glossterm>, and
+      <glossterm linkend="glossary-foreign-data-wrapper">foreign data wrappers</glossterm>.
     </para>
     <para>
       For more information, see
@@ -1373,7 +1413,7 @@
   </glossentry>
 
   <glossentry id="glossary-sql-standard">
-   <glossterm>SQL Standard</glossterm>
+   <glossterm>SQL standard</glossterm>
    <glossdef>
     <para>
      A series of documents that define the <acronym>SQL</acronym> language.
@@ -1382,11 +1422,11 @@
   </glossentry>
 
   <glossentry id="glossary-stats-collector">
-   <glossterm>Stats Collector</glossterm>
+   <glossterm>Stats collector</glossterm>
    <glossdef>
     <para>
      This process collects statistical information about the
-     <glossterm linkend="glossary-cluster">Cluster</glossterm>'s activities.
+     <glossterm linkend="glossary-instance">instance</glossterm>'s activities.
     </para>
     <para>
       For more information, see
@@ -1396,22 +1436,21 @@
   </glossentry>
 
   <glossentry id="glossary-system-catalog">
-   <glossterm>System Catalog</glossterm>
+   <glossterm>System catalog</glossterm>
    <glossdef>
     <para>
      A collection of <glossterm linkend="glossary-table">tables</glossterm>
      which describe the structure of all
      <glossterm linkend="glossary-sql-object">SQL objects</glossterm>
-     of each <glossterm linkend="glossary-database">database</glossterm>
-     and the <glossterm linkend="glossary-global-sql-object">global SQL objects</glossterm>
-     of the <glossterm linkend="glossary-cluster">cluster</glossterm>.
+     of the instance.
      The system catalog resides in the schema <literal>pg_catalog</literal>.
      These tables contain data in internal representation and are
      not typically considered useful for user examination;
      a number of user-friendlier <glossterm linkend="glossary-view">views</glossterm>
      also in schema <literal>pg_catalog</literal> offer more convenient access to
      some of that information, while additional tables and views
-     exist in schema <literal>information_schema</literal> that expose some
+     exist in schema <literal>information_schema</literal>
+     (see <xref linkend="information-schema" />) that expose some
      of the same and additional information as mandated by the
      <glossterm linkend="glossary-sql-standard">SQL standard</glossterm>.
     </para>
@@ -1431,7 +1470,7 @@
      <glossterm linkend="glossary-attribute">attributes</glossterm>, in the same
      order, having the same name and type per position).
      A table is the most common form of
-     <glossterm linkend="glossary-relation">Relation</glossterm> in
+     <glossterm linkend="glossary-relation">relation</glossterm> in
      <productname>PostgreSQL</productname>.
     </para>
     <para>
@@ -1461,7 +1500,7 @@
   </glossentry>
 
   <glossentry id="glossary-temporary-table">
-   <glossterm>Temporary Table</glossterm>
+   <glossterm>Temporary table</glossterm>
    <glossdef>
     <para>
      <glossterm linkend="glossary-table">Tables</glossterm> that exist either
@@ -1481,6 +1520,21 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-toast">
+   <glossterm>TOAST</glossterm>
+   <glossdef>
+    <para>
+     A mechanism by which large attributes of table rows are split and
+     stored in a secondary table, called the <firstterm>TOAST table</firstterm>.
+     Each relation with large attributes has its own TOAST table.
+    </para>
+    <para>
+     For more information, see
+     <xref linkend="storage-toast" />.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-transaction">
    <glossterm>Transaction</glossterm>
    <glossdef>
@@ -1499,6 +1553,30 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-xid">
+   <glossterm>Transaction ID</glossterm>
+   <glossdef>
+    <para>
+     The numerical, unique, sequentially-assigned identifier that each
+     transaction receives when it first causes a database modification.
+     Frequently abbreviated as <firstterm>xid</firstterm>.
+     When stored on disk, xids are only 32-bits wide, so only 
+     approximately four billion write transaction IDs can be generated;
+     to permit the system to run for longer than that,
+     <firstterm>epochs</firstterm> are used, also 32 bits wide.
+     When the counter reaches the maximum xid value, it starts over at
+     <literal>3</literal> (values under that are reserved) and the
+     epoch value is incremented by one.
+     In some contexts, the epoch and xid values are
+     considered together as a single 64-bit value.
+    </para>
+    <para>
+     For more information, see
+     <xref linkend="datatype-oid"/>.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-trigger">
    <glossterm>Trigger</glossterm>
    <glossdef>
@@ -1508,7 +1586,7 @@
      <command>UPDATE</command>, <command>DELETE</command>,
      <command>TRUNCATE</command>) is applied to a
      <glossterm linkend="glossary-relation">relation</glossterm>.
-     A Trigger executes within the same
+     A trigger executes within the same
      <glossterm linkend="glossary-transaction">transaction</glossterm> as the
      statement which invoked it, and if the function fails, then the invoking
      statement also fails.
@@ -1535,7 +1613,7 @@
   </glossentry>
 
   <glossentry id="glossary-unique-constraint">
-   <glossterm>Unique Constraint</glossterm>
+   <glossterm>Unique constraint</glossterm>
    <glossdef>
     <para>
      A type of <glossterm linkend="glossary-constraint">constraint</glossterm>
@@ -1577,7 +1655,7 @@
    <glossterm>Update</glossterm>
    <glossdef>
     <para>
-     A <acronym>SQL</acronym> command used to modify
+     An <acronym>SQL</acronym> command used to modify
      <glossterm linkend="glossary-tuple">rows</glossterm>
      that may already exist in a specified <glossterm linkend="glossary-table">table</glossterm>.
      It cannot create or remove rows.
@@ -1619,9 +1697,10 @@
    <glossterm>Vacuum</glossterm>
    <glossdef>
     <para>
-     The process of removing outdated <glossterm linkend="glossary-tuple">tuple
-     versions</glossterm> from tables, and other closely related
-     garbage-collection-like processing required by <productname>PostgreSQL</productname>'s
+     The process of removing outdated
+     <glossterm linkend="glossary-tuple">tuple versions</glossterm>
+     from tables or materialized views, and other closely related
+     processing required by <productname>PostgreSQL</productname>'s
      implementation of <glossterm linkend="glossary-mvcc">MVCC</glossterm>.
      This can be initiated through the use of
      the <command>VACUUM</command> command, but can also be handled automatically
@@ -1651,8 +1730,28 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-vm">
+   <glossterm>Visibility map (fork)</glossterm>
+   <glossdef>
+    <para>
+     A storage structure that keeps metadata about each data page
+     of a table's main fork.  The visibility map entry for
+     each page stores two bits: the first one
+     (<literal>all-visible</literal>) indicates that all tuples
+     in the page are visible to all transactions.  The second one
+     (<literal>all-frozen</literal>) indicate that all tuples
+     in the page are marked frozen.
+    </para>
+   </glossdef>
+  </glossentry>
+
+  <glossentry>
+   <glossterm>WAL</glossterm>
+   <glosssee otherterm="glossary-wal" />
+  </glossentry>
+
   <glossentry id="glossary-wal-archiver">
-   <glossterm>WAL Archiver (process)</glossterm>
+   <glossterm>WAL archiver (process)</glossterm>
    <glossdef>
     <para>
      A process that saves copies of <glossterm linkend="glossary-wal-file">WAL files</glossterm>
@@ -1667,7 +1766,7 @@
   </glossentry>
 
   <glossentry id="glossary-wal-file">
-   <glossterm>WAL File</glossterm>
+   <glossterm>WAL file</glossterm>
    <glossdef>
     <para>
      Also known as <firstterm>WAL segment</firstterm> or
@@ -1678,7 +1777,7 @@
      and are written in sequential order, interspersing changes
      as they occur in multiple simultaneous sessions.
      If the system crashes, the files are read in order, and each of the
-     changes are replayed to restore the system to the state as it was
+     changes is replayed to restore the system to the state as it was
      before the crash.
     </para>
     <para>
@@ -1696,13 +1795,8 @@
    </glossdef>
   </glossentry>
 
-  <glossentry>
-   <glossterm>WAL</glossterm>
-   <glosssee otherterm="glossary-wal" />
-  </glossentry>
-
   <glossentry id="glossary-wal-record">
-   <glossterm>WAL Record</glossterm>
+   <glossterm>WAL record</glossterm>
    <glossdef>
     <para>
      A low-level description of an individual data change.
@@ -1719,17 +1813,17 @@
   </glossentry>
 
   <glossentry>
-   <glossterm>WAL Segment</glossterm>
+   <glossterm>WAL segment</glossterm>
    <glosssee otherterm="glossary-wal-file" />
   </glossentry>
 
   <glossentry id="glossary-wal-writer">
-  <glossterm>WAL Writer (process)</glossterm>
+  <glossterm>WAL writer (process)</glossterm>
   <glossdef>
    <para>
     A process that writes <glossterm linkend="glossary-wal-record">WAL records</glossterm>
-    from <glossterm id="linkend-shared-memory">shared memory</glossterm> to
-    <glossterm id="linkend-wal-file">WAL files</glossterm>.
+    from <glossterm linkend="glossary-shared-memory">shared memory</glossterm> to
+    <glossterm linkend="glossary-wal-file">WAL files</glossterm>.
    </para>
    <para>
     For more information, see
@@ -1739,7 +1833,7 @@
   </glossentry>
 
   <glossentry id="glossary-window-function">
-   <glossterm>Window Function</glossterm>
+   <glossterm>Window function</glossterm>
    <glossdef>
     <para>
      A type of <glossterm linkend="glossary-function">function</glossterm> whose
@@ -1759,7 +1853,7 @@
   </glossentry>
 
   <glossentry id="glossary-wal">
-   <glossterm>Write-Ahead Log</glossterm>
+   <glossterm>Write-ahead log</glossterm>
    <glossdef>
     <para>
      The journal that keeps track of the changes in the
-- 
2.20.1

--- doc/src/sgml/glossary.sgml.orig	2020-05-16 23:30:01.132290237 +0200
+++ doc/src/sgml/glossary.sgml	2020-05-16 23:38:35.643371310 +0200
@@ -67,7 +67,7 @@
    <glossdef>
     <para>
      In reference to a <glossterm linkend="glossary-datum">datum</glossterm>:
-     the fact that its value that cannot be broken down into smaller
+     the fact that its value cannot be broken down into smaller
      components.
     </para>
    </glossdef>
@@ -360,7 +360,7 @@
      <glossterm linkend="glossary-constraint">integrity constraints</glossterm>.
      Transactions may be allowed to violate some of the constraints
      transiently before it commits, but if such violations are not resolved
-     by the time it commits, such transaction is automatically
+     by the time it commits, such a transaction is automatically
      <glossterm linkend="glossary-rollback">rolled back</glossterm>.
      This is one of the <acronym>ACID</acronym> properties.
     </para>
@@ -649,8 +649,8 @@
    <glossterm>Grant</glossterm>
    <glossdef>
     <para>
-     An <acronym>SQL</acronym> command that is used to allow
-     <glossterm linkend="glossary-user">users</glossterm> or
+     An <acronym>SQL</acronym> command that is used to allow a
+     <glossterm linkend="glossary-user">user</glossterm> or
      <glossterm linkend="glossary-role">role</glossterm> to access
      specific objects within the <glossterm linkend="glossary-database">database</glossterm>.
     </para>
@@ -887,7 +887,7 @@
    <glossdef>
     <para>
      A <glossterm linkend="glossary-relation">relation</glossterm> that is
-     defined in the same way that a a <glossterm linkend="glossary-view">view</glossterm>
+     defined in the same way that a <glossterm linkend="glossary-view">view</glossterm>
      is, but stores data in the same way that a
      <glossterm linkend="glossary-table">table</glossterm> does. It cannot be
      modified via <command>INSERT</command>, <command>UPDATE</command>, or
@@ -962,7 +962,7 @@
    <glossdef>
     <para>
      In reference to a <glossterm linkend="glossary-window-function">window function</glossterm>:
-     a partition is a user-defined criteria that identifies which neighboring
+     a partition is a user-defined criterion that identifies which neighboring
      <glossterm linkend="glossary-tuple">rows</glossterm> can be considered by the
      function.
     </para>
@@ -1446,8 +1446,8 @@
      The system catalog resides in the schema <literal>pg_catalog</literal>.
      These tables contain data in internal representation and are
      not typically considered useful for user examination;
-     a number of user-friendlier <glossterm linkend="glossary-view">views</glossterm>
-     also in schema <literal>pg_catalog</literal> offer more convenient access to
+     a number of user-friendlier <glossterm linkend="glossary-view">views</glossterm>,
+     also in schema <literal>pg_catalog</literal>, offer more convenient access to
      some of that information, while additional tables and views
      exist in schema <literal>information_schema</literal>
      (see <xref linkend="information-schema" />) that expose some
@@ -1739,7 +1739,7 @@
      each page stores two bits: the first one
      (<literal>all-visible</literal>) indicates that all tuples
      in the page are visible to all transactions.  The second one
-     (<literal>all-frozen</literal>) indicate that all tuples
+     (<literal>all-frozen</literal>) indicates that all tuples
      in the page are marked frozen.
     </para>
    </glossdef>
@@ -1755,7 +1755,7 @@
    <glossdef>
     <para>
      A process that saves copies of <glossterm linkend="glossary-wal-file">WAL files</glossterm>
-     for the purposes of creating backups or keeping
+     for the purpose of creating backups or keeping
      <glossterm linkend="glossary-replica">replicas</glossterm> current.
     </para>
     <para>
@@ -1777,7 +1777,7 @@
      and are written in sequential order, interspersing changes
      as they occur in multiple simultaneous sessions.
      If the system crashes, the files are read in order, and each of the
-     changes is replayed to restore the system to the state as it was
+     changes is replayed to restore the system to the state it was in
      before the crash.
     </para>
     <para>

diff --git a/doc/src/sgml/glossary.sgml b/doc/src/sgml/glossary.sgml
index 8bb1ea5d87..75f0dc9a8c 100644
--- a/doc/src/sgml/glossary.sgml
+++ b/doc/src/sgml/glossary.sgml
@@ -179,7 +179,7 @@
    <glossterm>Bloat</glossterm>
    <glossdef>
     <para>
-     Space in data pages which does not contain current row versions,
+     Space in data pages which does not contain relevant row versions,
      such as unused (free) space or outdated row versions.
     </para>
    </glossdef>
@@ -1388,23 +1388,27 @@
     <glossdef>
      <para>
       Any object that can be created with a <command>CREATE</command>
-      command.  Most objects are specific to one database, and are commonly
-      known as <firstterm>local objects</firstterm>.
+      command. Most objects are specific to one schema within
+      one database, and are commonly
+      known as <firstterm>local SQL objects</firstterm>.
+     </para>
+     <para>
+      Some of the SQL objects do not belong to a single schema but
+      are known in all schemas of a database. Examples are
+      <glossterm linkend="glossary-extension">extensions</glossterm> like
+      <glossterm linkend="glossary-foreign-data-wrapper">foreign data wrappers</glossterm>, and
+      <glossterm linkend="glossary-cast">data type casts</glossterm>.
+     </para>
+     <para>
+      Some others even belong to the complete cluster and are
+      known in all databases and all its schemas.
       <glossterm linkend="glossary-role">Roles</glossterm>,
       <glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
       replication origins, subscriptions for logical replication, and
-      databases themselves are not local SQL objects since they exist
-      entirely outside of any specific database;
-      they are called <firstterm>global objects</firstterm>.
+      all <firstterm>database names</firstterm> exist
+      entirely outside of any specific database.
+      They are called <firstterm>global SQL objects</firstterm>.
      </para>
-     <para>
-      Most local objects belong to a specific
-      <glossterm linkend="glossary-schema">schema</glossterm> in their containing database.
-      There also exist local objects that do not belong to schemas; some examples are
-      <glossterm linkend="glossary-extension">extensions</glossterm>,
-      <glossterm linkend="glossary-cast">data type casts</glossterm>, and
-      <glossterm linkend="glossary-foreign-data-wrapper">foreign data wrappers</glossterm>.
-    </para>
     <para>
       For more information, see
       <xref linkend="manage-ag-overview"/>.

diff --git a/doc/src/sgml/glossary.sgml b/doc/src/sgml/glossary.sgml
index 25b03f3b37..e29b55e5ac 100644
--- a/doc/src/sgml/glossary.sgml
+++ b/doc/src/sgml/glossary.sgml
@@ -395,15 +395,15 @@
     <para>
      The base directory on the filesystem of a
      <glossterm linkend="glossary-server">server</glossterm> that contains all
-     data files and subdirectories associated with an
-     <glossterm linkend="glossary-instance">instance</glossterm> (with the
-     exception of <glossterm linkend="glossary-tablespace">tablespaces</glossterm>).
+     data files and subdirectories associated with a
+     <glossterm linkend="glossary-db-cluster">database cluster</glossterm>
+     (with the exception of
+     <glossterm linkend="glossary-tablespace">tablespaces</glossterm>).
      The environment variable <literal>PGDATA</literal> is commonly used to
-     refer to the
-     <glossterm linkend="glossary-data-directory">data directory</glossterm>.
+     refer to the data directory.
     </para>
     <para>
-     An <glossterm linkend="glossary-instance">instance</glossterm>'s storage
+     A <glossterm linkend="glossary-instance">cluster</glossterm>'s storage
      space comprises the data directory plus any additional tablespaces.
     </para>
     <para>
@@ -418,7 +418,7 @@
    <glossdef>
     <para>
      A named collection of
-     <glossterm linkend="glossary-sql-object">SQL objects</glossterm>.
+     <glossterm linkend="glossary-sql-object">local SQL objects</glossterm>.
     </para>
     <para>
      For more information, see
@@ -427,6 +427,22 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-db-cluster">
+   <glossterm>Database cluster</glossterm>
+   <glossdef>
+    <para>
+     A collection of databases and global SQL objects,
+     and their common static and dynamic meta-data.
+     Sometimes referred to as a
+     <firstterm>cluster</firstterm>.
+    </para>
+    <para>
+     In <productname>PostgreSQL</productname>, the term
+     <firstterm>cluster</firstterm> is also sometimes used to refer to an instance.
+     (Don't confuse this term with the SQL command <command>CLUSTER</command>.)
+    </para>
+  </glossentry>
+
   <glossentry>
    <glossterm>Database server</glossterm>
    <glosssee otherterm="glossary-instance" />
@@ -634,7 +650,7 @@
    <glossterm>Function</glossterm>
    <glossdef>
     <para>
-     Any defined transformation of data. Many functions are already defined
+     A defined transformation of data.  Many functions are already defined
      within <productname>PostgreSQL</productname> itself, but user-defined
      ones can also be added.
     </para>
@@ -724,14 +740,12 @@
    <glossterm>Instance</glossterm>
    <glossdef>
     <para>
-     A set of databases and accompanying global SQL objects that are stored in
-     the same <glossterm linkend="glossary-data-directory">data directory</glossterm>
-     in a single <glossterm linkend="glossary-server">server</glossterm>.
-     If running, one
+     A group of backend and auxiliary processes that communicate using
+     a common shared memory area.  One 
      <glossterm linkend="glossary-postmaster">postmaster process</glossterm>
-     manages a group of backend and auxiliary processes that communicate
-     using a common <glossterm linkend="glossary-shared-memory">shared memory</glossterm>
-     area.  Many instances can run on the same
+     manages the instance; one instance manages exactly one
+     <glossterm linkend="glossary-db-cluster">database cluster</glossterm>
+     with all its databases.  Many instances can run on the same
      <glossterm linkend="glossary-server">server</glossterm>
      as long as their <acronym>TCP</acronym> ports do not conflict.
     </para>
@@ -739,14 +753,10 @@
      The instance handles all key features of a <acronym>DBMS</acronym>:
      read and write access to files and shared memory,
      assurance of the <acronym>ACID</acronym> properties,
-     <glossterm linkend="glossary-connection">connections</glossterm> to client processes,
+     <glossterm linkend="glossary-connection">connections</glossterm> to
+     <glossterm linkend="glossary-client">client processes</glossterm>,
      privilege verification, crash recovery, replication, etc.
     </para>
-    <para>
-     In <productname>PostgreSQL</productname>, the term
-     <firstterm>cluster</firstterm> is also sometimes used to refer to an instance.
-     (Don't confuse this term with the SQL command <command>CLUSTER</command>.)
-    </para>
    </glossdef>
   </glossentry>
 
@@ -1245,12 +1255,17 @@
      <glossterm linkend="glossary-sql-object">SQL objects</glossterm>,
      which all reside in the same
      <glossterm linkend="glossary-database">database</glossterm>.
-     Each SQL object must reside in exactly one schema.
+     Each SQL object must reside in exactly one schema
+     (though certain types of SQL objects exist outside schemas).
     </para>
     <para>
      The names of SQL objects of the same type in the same schema are enforced
      to be unique.
      There is no restriction on reusing a name in multiple schemas.
+     For local objects that exist outside schemas, their names are enforced
+     unique across the whole database.  For global objects, their names
+     are enforced unique across the whole
+     <glossterm linkend="glossary-db-cluster">database cluster</glossterm>.
     </para>
     <para>
      All system-defined SQL objects reside in schema <literal>pg_catalog</literal>,
@@ -1384,27 +1399,34 @@
   </glossentry>
 
   <glossentry id="glossary-sql-object">
-   <glossterm>SQL Object</glossterm>
+   <glossterm>SQL object</glossterm>
     <glossdef>
      <para>
       Any object that can be created with a <command>CREATE</command>
       command.  Most objects are specific to one database, and are commonly
       known as <firstterm>local objects</firstterm>.
-      <glossterm linkend="glossary-role">Roles</glossterm>,
-      <glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
-      replication origins, subscriptions for logical replication, and
-      databases themselves are not local SQL objects since they exist
-      entirely outside of any specific database;
-      they are called <firstterm>global objects</firstterm>.
      </para>
      <para>
       Most local objects belong to a specific
-      <glossterm linkend="glossary-schema">schema</glossterm> in their containing database.
+      <glossterm linkend="glossary-schema">schema</glossterm> in their
+      containing database, such as
+      <glossterm linkend="glossary-relation">all types of relations</glossterm>,
+      <glossterm linkend="glossary-function">all types of functions</glossterm>,
+      data types, etc.
       There also exist local objects that do not belong to schemas; some examples are
       <glossterm linkend="glossary-extension">extensions</glossterm>,
       <glossterm linkend="glossary-cast">data type casts</glossterm>, and
       <glossterm linkend="glossary-foreign-data-wrapper">foreign data wrappers</glossterm>.
-    </para>
+     </para>
+     <para>
+      Other object types, such as
+      <glossterm linkend="glossary-role">roles</glossterm>,
+      <glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
+      replication origins, subscriptions for logical replication, and
+      databases themselves are not local SQL objects since they exist
+      entirely outside of any specific database;
+      they are called <firstterm>global objects</firstterm>.
+     </para>
     <para>
       For more information, see
       <xref linkend="manage-ag-overview"/>.
@@ -1489,7 +1511,7 @@
      which require storage beyond their definition in the
      <glossterm linkend="glossary-system-catalog">system catalog</glossterm>
      must belong to a single tablespace.
-     Initially, an instance contains a single usable tablespace which is
+     Initially, a database cluster contains a single usable tablespace which is
      used as the default one for all SQL objects, called <literal>pg_default</literal>.
     </para>
     <para>

diff --git a/doc/src/sgml/glossary.sgml b/doc/src/sgml/glossary.sgml
index e29b55e5ac..0499f9044f 100644
--- a/doc/src/sgml/glossary.sgml
+++ b/doc/src/sgml/glossary.sgml
@@ -413,6 +413,22 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-data-page">
+   <glossterm>Data page</glossterm>
+   <glossdef>
+    <para>
+     The basic structure used to store relation data.
+     All pages are of the same size.
+     Data pages are typically stored on disk, each in a specific file,
+     and can be read to <glossterm linkend="glossary-shared-memory">shared buffers</glossterm>
+     where they can be modified, becoming
+     <firstterm>dirty</firstterm>.  They become clean when written
+     to disk.  New pages, which initially exist in memory only, are also
+     dirty until written.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-database">
    <glossterm>Database</glossterm>
    <glossdef>
@@ -441,6 +457,7 @@
      <firstterm>cluster</firstterm> is also sometimes used to refer to an instance.
      (Don't confuse this term with the SQL command <command>CLUSTER</command>.)
     </para>
+   </glossdef>
   </glossentry>
 
   <glossentry>
@@ -448,22 +465,6 @@
    <glosssee otherterm="glossary-instance" />
   </glossentry>
 
-  <glossentry id="glossary-data-page">
-   <glossterm>Data page</glossterm>
-   <glossdef>
-    <para>
-     The basic structure used to store relation data.
-     All pages are of the same size.
-     Data pages are typically stored on disk, each in a specific file,
-     and can be read to <glossterm linkend="glossary-shared-memory">shared buffers</glossterm>
-     where they can be modified, becoming
-     <firstterm>dirty</firstterm>.  They become clean when written
-     to disk.  New pages, which initially exist in memory only, are also
-     dirty until written.
-    </para>
-   </glossdef>
-  </glossentry>
-
   <glossentry id="glossary-datum">
    <glossterm>Datum</glossterm>
    <glossdef>

diff --git a/doc/src/sgml/glossary.sgml b/doc/src/sgml/glossary.sgml
index 25b03f3b37..5274feabba 100644
--- a/doc/src/sgml/glossary.sgml
+++ b/doc/src/sgml/glossary.sgml
@@ -23,7 +23,7 @@
   </glossentry>
 
   <glossentry id="glossary-aggregate">
-   <glossterm>Aggregate function</glossterm>
+   <glossterm>Aggregate function (routine)</glossterm>
    <glossdef>
     <para>
      A <glossterm linkend="glossary-function">function</glossterm> that
@@ -39,6 +39,11 @@
    </glossdef>
   </glossentry>
 
+  <glossentry>
+   <glossterm>Analytic function</glossterm>
+   <glosssee otherterm="glossary-window-function" />
+  </glossentry>
+
   <glossentry id="glossary-analyze">
    <glossterm>Analyze (operation)</glossterm>
    <glossdef>
@@ -57,11 +62,6 @@
    </glossdef>
   </glossentry>
 
-  <glossentry>
-   <glossterm>Analytic function</glossterm>
-   <glosssee otherterm="glossary-window-function" />
-  </glossentry>
-
   <glossentry id="glossary-atomic">
    <glossterm>Atomic</glossterm>
    <glossdef>
@@ -389,40 +389,33 @@
    <glosssee otherterm="glossary-data-directory" />
   </glossentry>
 
-  <glossentry id="glossary-data-directory">
-   <glossterm>Data directory</glossterm>
+  <glossentry id="glossary-database">
+   <glossterm>Database</glossterm>
    <glossdef>
     <para>
-     The base directory on the filesystem of a
-     <glossterm linkend="glossary-server">server</glossterm> that contains all
-     data files and subdirectories associated with an
-     <glossterm linkend="glossary-instance">instance</glossterm> (with the
-     exception of <glossterm linkend="glossary-tablespace">tablespaces</glossterm>).
-     The environment variable <literal>PGDATA</literal> is commonly used to
-     refer to the
-     <glossterm linkend="glossary-data-directory">data directory</glossterm>.
-    </para>
-    <para>
-     An <glossterm linkend="glossary-instance">instance</glossterm>'s storage
-     space comprises the data directory plus any additional tablespaces.
+     A named collection of
+     <glossterm linkend="glossary-sql-object">local SQL objects</glossterm>.
     </para>
     <para>
      For more information, see
-     <xref linkend="storage-file-layout"/>.
+     <xref linkend="manage-ag-overview"/>.
     </para>
    </glossdef>
   </glossentry>
 
-  <glossentry id="glossary-database">
-   <glossterm>Database</glossterm>
+  <glossentry id="glossary-db-cluster">
+   <glossterm>Database cluster</glossterm>
    <glossdef>
     <para>
-     A named collection of
-     <glossterm linkend="glossary-sql-object">SQL objects</glossterm>.
+     A collection of databases and global SQL objects,
+     and their common static and dynamic metadata.
+     Sometimes referred to as a
+     <firstterm>cluster</firstterm>.
     </para>
     <para>
-     For more information, see
-     <xref linkend="manage-ag-overview"/>.
+     In <productname>PostgreSQL</productname>, the term
+     <firstterm>cluster</firstterm> is also sometimes used to refer to an instance.
+     (Don't confuse this term with the SQL command <command>CLUSTER</command>.)
     </para>
    </glossdef>
   </glossentry>
@@ -432,6 +425,31 @@
    <glosssee otherterm="glossary-instance" />
   </glossentry>
 
+  <glossentry id="glossary-data-directory">
+   <glossterm>Data directory</glossterm>
+   <glossdef>
+    <para>
+     The base directory on the filesystem of a
+     <glossterm linkend="glossary-server">server</glossterm> that contains all
+     data files and subdirectories associated with a
+     <glossterm linkend="glossary-db-cluster">database cluster</glossterm>
+     (with the exception of
+     <glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
+     and optionally <glossterm linkend="glossary-wal">WAL</glossterm>).
+     The environment variable <literal>PGDATA</literal> is commonly used to
+     refer to the data directory.
+    </para>
+    <para>
+     A <glossterm linkend="glossary-db-cluster">cluster</glossterm>'s storage
+     space comprises the data directory plus any additional tablespaces.
+    </para>
+    <para>
+     For more information, see
+     <xref linkend="storage-file-layout"/>.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-data-page">
    <glossterm>Data page</glossterm>
    <glossdef>
@@ -578,7 +596,7 @@
   </glossentry>
 
   <glossentry id="glossary-foreign-table">
-   <glossterm>Foreign table</glossterm>
+   <glossterm>Foreign table (relation)</glossterm>
    <glossdef>
     <para>
      A <glossterm linkend="glossary-relation">relation</glossterm> which appears to have
@@ -631,12 +649,20 @@
   </glossentry>
 
   <glossentry id="glossary-function">
-   <glossterm>Function</glossterm>
+   <glossterm>Function (routine)</glossterm>
    <glossdef>
     <para>
-     Any defined transformation of data. Many functions are already defined
-     within <productname>PostgreSQL</productname> itself, but user-defined
-     ones can also be added.
+     A type of routine that receives zero or more arguments, returns zero or more
+     output values, and is constrained to run within one transaction.
+     Functions are invoked as part of a query, for example via
+     <command>SELECT</command>.
+     Certain functions can return
+     <glossterm linkend="glossary-result-set">sets</glossterm>; those are
+     called <firstterm>set-returning functions</firstterm>.
+    </para>
+    <para>
+     Functions can also be used for
+     <glossterm linkend="glossary-trigger">triggers</glossterm> to invoke.
     </para>
     <para>
      For more information, see
@@ -689,13 +715,12 @@
   </glossentry>
 
   <glossentry id="glossary-index">
-   <glossterm>Index</glossterm>
+   <glossterm>Index (relation)</glossterm>
    <glossdef>
     <para>
      A <glossterm linkend="glossary-relation">relation</glossterm> that contains
      data derived from a <glossterm linkend="glossary-table">table</glossterm>
-     (or <glossterm linkend="glossary-relation">relation</glossterm> types
-     such as a <glossterm linkend="glossary-materialized-view">materialized view</glossterm>).
+     or <glossterm linkend="glossary-materialized-view">materialized view</glossterm>.
      Its internal structure supports fast retrieval of and access to the original
      data.
     </para>
@@ -724,14 +749,12 @@
    <glossterm>Instance</glossterm>
    <glossdef>
     <para>
-     A set of databases and accompanying global SQL objects that are stored in
-     the same <glossterm linkend="glossary-data-directory">data directory</glossterm>
-     in a single <glossterm linkend="glossary-server">server</glossterm>.
-     If running, one
+     A group of backend and auxiliary processes that communicate using
+     a common shared memory area.  One 
      <glossterm linkend="glossary-postmaster">postmaster process</glossterm>
-     manages a group of backend and auxiliary processes that communicate
-     using a common <glossterm linkend="glossary-shared-memory">shared memory</glossterm>
-     area.  Many instances can run on the same
+     manages the instance; one instance manages exactly one
+     <glossterm linkend="glossary-db-cluster">database cluster</glossterm>
+     with all its databases.  Many instances can run on the same
      <glossterm linkend="glossary-server">server</glossterm>
      as long as their <acronym>TCP</acronym> ports do not conflict.
     </para>
@@ -739,14 +762,10 @@
      The instance handles all key features of a <acronym>DBMS</acronym>:
      read and write access to files and shared memory,
      assurance of the <acronym>ACID</acronym> properties,
-     <glossterm linkend="glossary-connection">connections</glossterm> to client processes,
+     <glossterm linkend="glossary-connection">connections</glossterm> to
+     <glossterm linkend="glossary-client">client processes</glossterm>,
      privilege verification, crash recovery, replication, etc.
     </para>
-    <para>
-     In <productname>PostgreSQL</productname>, the term
-     <firstterm>cluster</firstterm> is also sometimes used to refer to an instance.
-     (Don't confuse this term with the SQL command <command>CLUSTER</command>.)
-    </para>
    </glossdef>
   </glossentry>
 
@@ -769,8 +788,10 @@
    <glossterm>Join</glossterm>
    <glossdef>
     <para>
-     An <acronym>SQL</acronym> keyword used in <command>SELECT</command> statements for
-     combining data from multiple <glossterm linkend="glossary-relation">relations</glossterm>.
+     An operation and <acronym>SQL</acronym> keyword used in
+     <glossterm linkend="glossary-query">queries</glossterm>
+     for combining data from multiple
+     <glossterm linkend="glossary-relation">relations</glossterm>.
     </para>
    </glossdef>
   </glossentry>
@@ -781,10 +802,10 @@
     <para>
      A means of identifying a <glossterm linkend="glossary-tuple">row</glossterm> within a
      <glossterm linkend="glossary-table">table</glossterm> or
-     <glossterm linkend="glossary-relation">relation</glossterm> by
+     other <glossterm linkend="glossary-relation">relation</glossterm> by
      values contained within one or more
      <glossterm linkend="glossary-attribute">attributes</glossterm>
-     in that table.
+     in that relation.
     </para>
    </glossdef>
   </glossentry>
@@ -813,15 +834,6 @@
    </glossdef>
   </glossentry>
 
-  <glossentry id="glossary-log-record">
-   <glossterm>Log record</glossterm>
-    <glossdef>
-     <para>
-      Archaic term for a <glossterm linkend="glossary-wal-record">WAL record</glossterm>.
-     </para>
-    </glossdef>
-  </glossentry>
-
   <glossentry id="glossary-logged">
    <glossterm>Logged</glossterm>
    <glossdef>
@@ -855,6 +867,15 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-log-record">
+   <glossterm>Log record</glossterm>
+    <glossdef>
+     <para>
+      Archaic term for a <glossterm linkend="glossary-wal-record">WAL record</glossterm>.
+     </para>
+    </glossdef>
+  </glossentry>
+
   <glossentry>
    <glossterm>Master (server)</glossterm>
    <glosssee otherterm="glossary-primary-server" />
@@ -883,12 +904,13 @@
   </glossentry>
 
   <glossentry id="glossary-materialized-view">
-   <glossterm>Materialized view</glossterm>
+   <glossterm>Materialized view (relation)</glossterm>
    <glossdef>
     <para>
      A <glossterm linkend="glossary-relation">relation</glossterm> that is
-     defined in the same way that a <glossterm linkend="glossary-view">view</glossterm>
-     is, but stores data in the same way that a
+     defined by a <command>SELECT</command> statement
+     (just like a <glossterm linkend="glossary-view">view</glossterm>),
+     but stores data in the same way that a
      <glossterm linkend="glossary-table">table</glossterm> does. It cannot be
      modified via <command>INSERT</command>, <command>UPDATE</command>, or
      <command>DELETE</command> operations.
@@ -949,6 +971,8 @@
     <para>
      One of several disjoint (not overlapping) subsets of a larger set.
     </para>
+   </glossdef>
+   <glossdef>
     <para>
      In reference to a
      <glossterm linkend="glossary-partitioned-table">partitioned table</glossterm>:
@@ -961,16 +985,18 @@
    </glossdef>
    <glossdef>
     <para>
-     In reference to a <glossterm linkend="glossary-window-function">window function</glossterm>:
+     In reference to a <glossterm linkend="glossary-window-function">window function</glossterm>
+     in a <glossterm linkend="glossary-query">query</glossterm>,
      a partition is a user-defined criterion that identifies which neighboring
-     <glossterm linkend="glossary-tuple">rows</glossterm> can be considered by the
-     function.
+     <glossterm linkend="glossary-tuple">rows</glossterm>
+     of the <glossterm linkend="glossary-result-set">query's result set</glossterm>
+     can be considered by the function.
     </para>
    </glossdef>
   </glossentry>
 
   <glossentry id="glossary-partitioned-table">
-   <glossterm>Partitioned table</glossterm>
+   <glossterm>Partitioned table (relation)</glossterm>
    <glossdef>
     <para>
      A <glossterm linkend="glossary-relation">relation</glossterm> that is
@@ -997,20 +1023,6 @@
    </glossdef>
   </glossentry>
 
-  <glossentry id="glossary-primary-server">
-   <glossterm>Primary (server)</glossterm>
-   <glossdef>
-    <para>
-     When two or more <glossterm linkend="glossary-database">databases</glossterm>
-     are linked via <glossterm linkend="glossary-replication">replication</glossterm>,
-     the <glossterm linkend="glossary-server">server</glossterm>
-     that is considered the authoritative source of information is called
-     the <firstterm>primary</firstterm>,
-     also known as a <firstterm>master</firstterm>.
-    </para>
-   </glossdef>
-  </glossentry>
-
   <glossentry id="glossary-primary-key">
    <glossterm>Primary key</glossterm>
    <glossdef>
@@ -1031,19 +1043,29 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-primary-server">
+   <glossterm>Primary (server)</glossterm>
+   <glossdef>
+    <para>
+     When two or more <glossterm linkend="glossary-database">databases</glossterm>
+     are linked via <glossterm linkend="glossary-replication">replication</glossterm>,
+     the <glossterm linkend="glossary-server">server</glossterm>
+     that is considered the authoritative source of information is called
+     the <firstterm>primary</firstterm>,
+     also known as a <firstterm>master</firstterm>.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-procedure">
-   <glossterm>Procedure</glossterm>
+   <glossterm>Procedure (routine)</glossterm>
    <glossdef>
     <para>
-     A defined set of instructions for manipulating data within a
-     <glossterm linkend="glossary-database">database</glossterm>.
-     A <glossterm linkend="glossary-procedure">procedure</glossterm> can
-     be written in a variety of programming languages. They are
-     similar to <glossterm linkend="glossary-function">functions</glossterm>,
-     but are different in that they must be invoked via the <command>CALL</command>
-     command rather than the <command>SELECT</command> or <command>PERFORM</command>
-     commands, and they are allowed to make transactional statements such
+     A type of routine.
+     Their distinctive qualities are that they do not return values,
+     and that they are allowed to make transactional statements such
      as <command>COMMIT</command> and <command>ROLLBACK</command>.
+     They are invoked via the <command>CALL</command> command.
     </para>
     <para>
      For more information, see
@@ -1115,6 +1137,11 @@
      <glossterm linkend="glossary-index">indexes</glossterm> are all relations.
     </para>
     <para>
+     More generically, a relation is a set of tuples; for example,
+     the result of a query is also a relation.
+    </para>
+    <para>
+     In <productname>PostgreSQL</productname>,
      <firstterm>Class</firstterm> is an archaic synonym for
      <firstterm>relation</firstterm>.
     </para>
@@ -1155,16 +1182,23 @@
    <glossterm>Result set</glossterm>
    <glossdef>
     <para>
-     A data structure transmitted from a
-     <glossterm linkend="glossary-backend">backend process</glossterm> to
-     a <glossterm linkend="glossary-client">client</glossterm> upon the
-     completion of an <acronym>SQL</acronym>
-     command, usually a <command>SELECT</command> but it can be an
+     A <glossterm linkend="glossary-relation">relation</glossterm> transmitted
+     from a <glossterm linkend="glossary-backend">backend process</glossterm>
+     to a <glossterm linkend="glossary-client">client</glossterm> upon the
+     completion of an <acronym>SQL</acronym> command, usually a
+     <command>SELECT</command> but it can be an
      <command>INSERT</command>, <command>UPDATE</command>, or
      <command>DELETE</command> command if the <literal>RETURNING</literal>
-     clause is specified. The data structure consists of zero or more
-     <glossterm linkend="glossary-tuple">rows</glossterm> with the same ordered set of
-     <glossterm linkend="glossary-attribute">attributes</glossterm>.
+     clause is specified.
+    </para>
+    <para>
+     The fact that a result set is a relation means that a query can be used
+     in the definition of another query, becoming a
+     <firstterm>subquery</firstterm>.
+    </para>
+   </glossdef>
+   <glossdef>
+    <para>
     </para>
    </glossdef>
   </glossentry>
@@ -1216,6 +1250,27 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-routine">
+   <glossterm>Routine</glossterm>
+   <glossdef>
+    <para>
+     A defined set of instructions stored in the database system
+     that can be invoked for execution.
+     A routine can be written in a variety of programming
+     languages.  Routines can be
+     <glossterm linkend="glossary-function">functions</glossterm>
+     (including set-returning functions and
+     <glossterm linkend="glossary-trigger">trigger functions</glossterm>),
+     <glossterm linkend="glossary-aggregate">aggregates functions</glossterm>,
+     and <glossterm linkend="glossary-procedure">procedures</glossterm>.
+    </para>
+    <para>
+     Many routines are already defined within <productname>PostgreSQL</productname>
+     itself, but user-defined ones can also be added.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry>
    <glossterm>Row</glossterm>
    <glosssee otherterm="glossary-tuple" />
@@ -1248,16 +1303,7 @@
      Each SQL object must reside in exactly one schema.
     </para>
     <para>
-     The names of SQL objects of the same type in the same schema are enforced
-     to be unique.
-     There is no restriction on reusing a name in multiple schemas.
-    </para>
-    <para>
-     All system-defined SQL objects reside in schema <literal>pg_catalog</literal>,
-     and commonly many user-defined SQL objects reside in the default schema
-     <literal>public</literal>,
-     but it is common and recommended that other schemas are created to hold
-     application-specific SQL objects.
+     All system-defined SQL objects reside in schema <literal>pg_catalog</literal>.
     </para>
    </glossdef>
    <glossdef>
@@ -1299,6 +1345,19 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-sequence">
+   <glossterm>Sequence (relation)</glossterm>
+   <glossdef>
+    <para>
+     A type of relation that is used to generate values.
+     Typically the generated values are sequential non-repeating numbers.
+     They are commonly used to generate surrogate
+     <glossterm linkend="glossary-primary-key">primary key</glossterm>
+     values.
+    </para>
+   </glossdef>
+  </glossentry>
+
 <!--  XXX should define all other isolation levels (and improve this definition)
   <glossentry id="glossary-serializable">
    <glossterm>Serializable (isolation level)</glossterm>
@@ -1339,19 +1398,6 @@
    </glossdef>
   </glossentry>
 
-  <glossentry id="glossary-sequence">
-   <glossterm>Sequence</glossterm>
-   <glossdef>
-    <para>
-     A type of relation that is used to generate values.
-     Typically the generated values are sequential non-repeating numbers.
-     They are commonly used to generate surrogate
-     <glossterm linkend="glossary-primary-key">primary key</glossterm>
-     values.
-    </para>
-   </glossdef>
-  </glossentry>
-
   <glossentry id="glossary-shared-memory">
    <glossterm>Shared memory</glossterm>
    <glossdef>
@@ -1378,33 +1424,43 @@
    </glossdef>
   </glossentry>
 
-  <glossentry>
-   <glossterm>Standby (server)</glossterm>
-   <glosssee otherterm="glossary-replica" />
-  </glossentry>
-
   <glossentry id="glossary-sql-object">
-   <glossterm>SQL Object</glossterm>
+   <glossterm>SQL object</glossterm>
     <glossdef>
      <para>
       Any object that can be created with a <command>CREATE</command>
       command.  Most objects are specific to one database, and are commonly
       known as <firstterm>local objects</firstterm>.
-      <glossterm linkend="glossary-role">Roles</glossterm>,
-      <glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
-      replication origins, subscriptions for logical replication, and
-      databases themselves are not local SQL objects since they exist
-      entirely outside of any specific database;
-      they are called <firstterm>global objects</firstterm>.
      </para>
      <para>
       Most local objects belong to a specific
-      <glossterm linkend="glossary-schema">schema</glossterm> in their containing database.
+      <glossterm linkend="glossary-schema">schema</glossterm> in their
+      containing database, such as
+      <glossterm linkend="glossary-relation">relations</glossterm> (all types),
+      <glossterm linkend="glossary-function">routines</glossterm> (all types),
+      data types, etc.
+      The name of such objects of the same type in the same schema
+      are enforced unique.
+     </para>
+     <para>
       There also exist local objects that do not belong to schemas; some examples are
       <glossterm linkend="glossary-extension">extensions</glossterm>,
       <glossterm linkend="glossary-cast">data type casts</glossterm>, and
       <glossterm linkend="glossary-foreign-data-wrapper">foreign data wrappers</glossterm>.
-    </para>
+      The name of such objects of the same type are enforced unique
+      within the database.
+     </para>
+     <para>
+      Other object types, such as
+      <glossterm linkend="glossary-role">roles</glossterm>,
+      <glossterm linkend="glossary-tablespace">tablespaces</glossterm>,
+      replication origins, subscriptions for logical replication, and
+      databases themselves are not local SQL objects since they exist
+      entirely outside of any specific database;
+      they are called <firstterm>global objects</firstterm>.
+      The names of such objects are enforced unique within the whole
+      database cluster.
+     </para>
     <para>
       For more information, see
       <xref linkend="manage-ag-overview"/>.
@@ -1421,6 +1477,11 @@
    </glossdef>
   </glossentry>
 
+  <glossentry>
+   <glossterm>Standby (server)</glossterm>
+   <glosssee otherterm="glossary-replica" />
+  </glossentry>
+
   <glossentry id="glossary-stats-collector">
    <glossterm>Stats collector</glossterm>
    <glossdef>
@@ -1489,8 +1550,8 @@
      which require storage beyond their definition in the
      <glossterm linkend="glossary-system-catalog">system catalog</glossterm>
      must belong to a single tablespace.
-     Initially, an instance contains a single usable tablespace which is
-     used as the default one for all SQL objects, called <literal>pg_default</literal>.
+     Initially, a database cluster contains a single usable tablespace which is
+     used as the default for all SQL objects, called <literal>pg_default</literal>.
     </para>
     <para>
      For more information, see
@@ -1577,6 +1638,18 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-tps">
+   <glossterm>Transactions per second (TPS)</glossterm>
+   <glossdef>
+    <para>
+     Average number of transactions that are executed per second,
+     totalled across all sessions active for a measured run.
+     This is used as a measure of the performance characteristics of
+     an instance.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-trigger">
    <glossterm>Trigger</glossterm>
    <glossdef>
@@ -1818,28 +1891,32 @@
   </glossentry>
 
   <glossentry id="glossary-wal-writer">
-  <glossterm>WAL writer (process)</glossterm>
-  <glossdef>
-   <para>
-    A process that writes <glossterm linkend="glossary-wal-record">WAL records</glossterm>
-    from <glossterm linkend="glossary-shared-memory">shared memory</glossterm> to
-    <glossterm linkend="glossary-wal-file">WAL files</glossterm>.
-   </para>
-   <para>
-    For more information, see
-    <xref linkend="runtime-config-wal"/>.
-   </para>
-  </glossdef>
+   <glossterm>WAL writer (process)</glossterm>
+   <glossdef>
+    <para>
+     A process that writes <glossterm linkend="glossary-wal-record">WAL records</glossterm>
+     from <glossterm linkend="glossary-shared-memory">shared memory</glossterm> to
+     <glossterm linkend="glossary-wal-file">WAL files</glossterm>.
+    </para>
+    <para>
+     For more information, see
+     <xref linkend="runtime-config-wal"/>.
+    </para>
+   </glossdef>
   </glossentry>
 
   <glossentry id="glossary-window-function">
-   <glossterm>Window function</glossterm>
+   <glossterm>Window function (routine)</glossterm>
    <glossdef>
     <para>
-     A type of <glossterm linkend="glossary-function">function</glossterm> whose
-     result is based on values found in
-     <glossterm linkend="glossary-tuple">rows</glossterm> of the same
-     <glossterm linkend="glossary-partition">partition</glossterm>.
+     A type of <glossterm linkend="glossary-function">function</glossterm>
+     used in a <glossterm linkend="glossary-query">query</glossterm>
+     that applies to a <glossterm linkend="glossary-partition">partition</glossterm>
+     of the query's <glossterm linkend="glossary-result-set">result set</glossterm>;
+     the function's result is based on values found in
+     <glossterm linkend="glossary-tuple">rows</glossterm> of the same partition or frame.
+    </para>
+    <para>
      All <glossterm linkend="glossary-aggregate">aggregate functions</glossterm>
      can be used as window functions, but window functions can also be
      used to, for example, give ranks to each of the rows in the partition.
@@ -1857,8 +1934,8 @@
    <glossdef>
     <para>
      The journal that keeps track of the changes in the
-     <glossterm linkend="glossary-instance">instance</glossterm> as user- and
-     system-invoked operations take place.
+     <glossterm linkend="glossary-db-cluster">database cluster</glossterm>
+     as user- and system-invoked operations take place.
      It comprises many individual
      <glossterm linkend="glossary-wal-record">WAL records</glossterm> written
      sequentially to <glossterm linkend="glossary-wal-file">WAL files</glossterm>.

diff --git a/doc/src/sgml/glossary.sgml b/doc/src/sgml/glossary.sgml
index 76525c6302..58e5071642 100644
--- a/doc/src/sgml/glossary.sgml
+++ b/doc/src/sgml/glossary.sgml
@@ -108,7 +108,7 @@
   </glossentry>
 
   <glossentry id="glossary-autovacuum">
-   <glossterm>Autovacuum</glossterm>
+   <glossterm>Autovacuum (process)</glossterm>
    <glossdef>
     <para>
      A set of background processes that routinely perform
@@ -178,6 +178,19 @@
    </glossdef>
   </glossentry>
 
+  <glossentry id="glossary-basebackup">
+   <glossterm>Base Backup</glossterm>
+   <glossdef>
+    <para>
+     A binary copy of all
+     <glossterm linkend="glossary-db-cluster">database cluster</glossterm>
+     files. It is generated by the tool <xref linkend="app-pgbasebackup"/>.  
+     In combination with WAL files it can be used as the starting point
+     for recovery, log shipping, or streaming replication.
+    </para>
+   </glossdef>
+  </glossentry>
+
   <glossentry id="glossary-bloat">
    <glossterm>Bloat</glossterm>
    <glossdef>
@@ -855,8 +868,7 @@
    <glossterm>Logger (process)</glossterm>
    <glossdef>
     <para>
-     If activated, the
-     <glossterm linkend="glossary-logger">Logger</glossterm> process
+     If activated, the process
      writes information about database events into the current
      <glossterm linkend="glossary-log-file">log file</glossterm>.
      When reaching certain time- or
@@ -1486,7 +1498,7 @@
   </glossentry>
 
   <glossentry id="glossary-stats-collector">
-   <glossterm>Stats collector</glossterm>
+   <glossterm>Stats collector (process)</glossterm>
    <glossdef>
     <para>
      This process collects statistical information about the