Doc: clean up some places that mentioned template1 but not template0.

tglsfdc · tglsfdc · commit 7d9ec0754afe · 2021-11-02T12:54:35.000-04:00
Improve old text that wasn't updated when we added template0 to the standard database set. Per suggestion from P. Luzanov. Discussion: https://postgr.es/m/163583775122.675.3700595100340939507@wrigleys.postgresql.org
diff --git a/doc/src/sgml/manage-ag.sgml b/doc/src/sgml/manage-ag.sgml
@@ -136,15 +136,21 @@ CREATE DATABASE <replaceable>name</replaceable>;
   </para>
 
   <para>
-   A second database,
-   <literal>template1</literal>,<indexterm><primary>template1</primary></indexterm>
-   is also created during database cluster initialization.  Whenever a
+   Two additional databases,
+   <literal>template1</literal><indexterm><primary>template1</primary></indexterm>
+   and
+   <literal>template0</literal>,<indexterm><primary>template0</primary></indexterm>
+   are also created during database cluster initialization.  Whenever a
    new database is created within the
    cluster, <literal>template1</literal> is essentially cloned.
    This means that any changes you make in <literal>template1</literal> are
    propagated to all subsequently created databases. Because of this,
    avoid creating objects in <literal>template1</literal> unless you want them
-   propagated to every newly created database.  More details
+   propagated to every newly created database.
+   <literal>template0</literal> is meant as a pristine copy of the original
+   contents of <literal>template1</literal>.  It can be cloned instead
+   of <literal>template1</literal> when it is important to make a database
+   without any such site-local additions.  More details
    appear in <xref linkend="manage-ag-templatedbs"/>.
   </para>
 
diff --git a/doc/src/sgml/ref/initdb.sgml b/doc/src/sgml/ref/initdb.sgml
@@ -46,13 +46,16 @@ PostgreSQL documentation
    Creating a database cluster consists of creating the directories in
    which the database data will live, generating the shared catalog
    tables (tables that belong to the whole cluster rather than to any
-   particular database), and creating the <literal>template1</literal>
-   and <literal>postgres</literal> databases. When you later create a
-   new database, everything in the <literal>template1</literal> database is
-   copied.  (Therefore, anything installed in <literal>template1</literal>
-   is automatically copied into each database created later.)
+   particular database), and creating the <literal>postgres</literal>,
+   <literal>template1</literal>, and <literal>template0</literal> databases.
    The <literal>postgres</literal> database is a default database meant
    for use by users, utilities and third party applications.
+   <literal>template1</literal> and <literal>template0</literal> are
+   meant as source databases to be copied by later <command>CREATE
+   DATABASE</command> commands.  <literal>template0</literal> should never
+   be modified, but you can add objects to <literal>template1</literal>,
+   which by default will be copied into databases created later.  See
+   <xref linkend="manage-ag-templatedbs"/> for more details.
   </para>
 
   <para>
@@ -88,7 +91,7 @@ PostgreSQL documentation
    collation order (<literal>LC_COLLATE</literal>) and character set classes
    (<literal>LC_CTYPE</literal>, e.g., upper, lower, digit) can be set separately
    for a database when it is created. <command>initdb</command> determines
-   those settings for the <literal>template1</literal> database, which will
+   those settings for the template databases, which will
    serve as the default for all other databases.
   </para>
 
@@ -184,9 +187,9 @@ PostgreSQL documentation
       <term><option>--encoding=<replaceable class="parameter">encoding</replaceable></option></term>
       <listitem>
        <para>
-        Selects the encoding of the template database. This will also
+        Selects the encoding of the template databases. This will also
         be the default encoding of any database you create later,
-        unless you override it there.  The default is derived from the locale, or
+        unless you override it then.  The default is derived from the locale, or
         <literal>SQL_ASCII</literal> if that does not work. The character sets supported by
         the <productname>PostgreSQL</productname> server are described
         in <xref linkend="multibyte-charset-supported"/>.
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
@@ -74,10 +74,10 @@
    which is meant as a default database for use by utilities, users and third
    party applications.  The database server itself does not require the
    <literal>postgres</literal> database to exist, but many external utility
-   programs assume it exists.  Another database created within each cluster
-   during initialization is called
-   <literal>template1</literal>.  As the name suggests, this will be used
-   as a template for subsequently created databases; it should not be
+   programs assume it exists.  There are two more databases created within
+   each cluster during initialization, named <literal>template1</literal>
+   and <literal>template0</literal>.  As the names suggest, these will be
+   used as templates for subsequently-created databases; they should not be
    used for actual work.  (See <xref linkend="managing-databases"/> for
    information about creating new databases within a cluster.)
   </para>
