DOC: updated pg-variables docs as per PGPRO-1420

Author: Liudmila Mantrova

doc/src/sgml/pg_variables.sgml

@@ -13,12 +13,12 @@
       example:
     </para>
 <programlisting>
-SELECT pgv_set_int('vars', 'int1', 101);
+postgres=# SELECT pgv_set_int('vars', 'int1', 101);
 BEGIN;
-SELECT pgv_set_int('vars', 'int2', 102);
+postgres=# SELECT pgv_set_int('vars', 'int2', 102);
 ROLLBACK;
 
-SELECT * FROM pgv_list() order by package, name;
+postgres=# SELECT * FROM pgv_list() ORDER BY package, name;
  package | name
 ---------+------
  vars    | int1
@@ -27,8 +27,21 @@ SELECT * FROM pgv_list() order by package, name;
 </programlisting>
   </sect2>
 
+  <sect2>
+    <title>Installation</title>
+     <para>
+        The <filename>pg_variables</filename> extension is included into
+        &productname;. Once you have &productname; installed, you must
+        execute the <xref linkend="sql-createextension"> command to enable
+        <filename>pg_variables</filename>, as follows:
+        <programlisting>
+CREATE EXTENSION pg_variables;
+</programlisting>
+     </para>
+  </sect2>
+
   <sect2 id="pg-variables-functions">
-    <title>Module functions</title>
+    <title>Functions</title>
 
     <para>
       The functions provided by the <filename>pg_variables</filename> module are
@@ -47,7 +60,7 @@ SELECT * FROM pgv_list() order by package, name;
     </para>
 
 <programlisting>
-SELECT pgv_get_int('vars', 'int1');
+postgres=# SELECT pgv_get_int('vars', 'int1');
 ERROR:  unrecognized package "vars"
 </programlisting>
 
@@ -56,7 +69,7 @@ ERROR:  unrecognized package "vars"
     </para>
 
 <programlisting>
-SELECT pgv_get_int('vars', 'int1');
+postgres=# SELECT pgv_get_int('vars', 'int1');
 ERROR:  unrecognized variable "int1"
 </programlisting>
 
@@ -66,7 +79,7 @@ ERROR:  unrecognized variable "int1"
     </para>
 
 <programlisting>
-SELECT pgv_get_text('vars', 'int1');
+postgres=# SELECT pgv_get_text('vars', 'int1');
 ERROR:  variable "int1" requires "integer" value
 </programlisting>
 
@@ -537,16 +550,16 @@ ERROR:  variable "int1" requires "integer" value
       It is easy to use functions to work with scalar variables:
     </para>
 <programlisting>
-SELECT pgv_set_int('vars', 'int1', 101);
-SELECT pgv_set_int('vars', 'int2', 102);
+postgres=# SELECT pgv_set_int('vars', 'int1', 101);
+postgres=# SELECT pgv_set_int('vars', 'int2', 102);
 
-SELECT pgv_get_int('vars', 'int1');
+postgres=# SELECT pgv_get_int('vars', 'int1');
  pgv_get_int 
 -------------
          101
 (1 row)
 
-SELECT pgv_get_int('vars', 'int2');
+postgres=# SELECT pgv_get_int('vars', 'int2');
  pgv_get_int 
 -------------
          102
@@ -563,37 +576,37 @@ INSERT INTO tab VALUES (0, 'str00'), (1, 'str11');
       Then you can use functions to work with record variables:
     </para>
 <programlisting>
-SELECT pgv_insert('vars', 'r1', tab) FROM tab;
+postgres=# SELECT pgv_insert('vars', 'r1', tab) FROM tab;
 
-SELECT pgv_select('vars', 'r1');
+postgres=# SELECT pgv_select('vars', 'r1');
  pgv_select
 ------------
  (1,str11)
  (0,str00)
 (2 rows)
 
-SELECT pgv_select('vars', 'r1', 1);
+postgres=# pgv_select('vars', 'r1', 1);
  pgv_select
 ------------
  (1,str11)
 (1 row)
 
-SELECT pgv_select('vars', 'r1', 0);
+postgres=# SELECT pgv_select('vars', 'r1', 0);
  pgv_select
 ------------
  (0,str00)
 (1 row)
 
-SELECT pgv_select('vars', 'r1', ARRAY[1, 0]);
+postgres=# SELECT pgv_select('vars', 'r1', ARRAY[1, 0]);
  pgv_select
 ------------
  (1,str11)
  (0,str00)
 (2 rows)
 
-SELECT pgv_delete('vars', 'r1', 1);
+postgres=# SELECT pgv_delete('vars', 'r1', 1);
 
-SELECT pgv_select('vars', 'r1');
+postgres=# SELECT pgv_select('vars', 'r1');
  pgv_select
 ------------
  (0,str00)
@@ -603,7 +616,7 @@ SELECT pgv_select('vars', 'r1');
       You can list packages and variables:
     </para>
 <programlisting>
-SELECT * FROM pgv_list() order by package, name;
+postgres=# SELECT * FROM pgv_list() ORDER BY package, name;
  package | name 
 ---------+------
  vars    | int1
@@ -615,7 +628,7 @@ SELECT * FROM pgv_list() order by package, name;
       And get used memory in bytes:
     </para>
 <programlisting>
-SELECT * FROM pgv_stats() order by package;
+postgres=# SELECT * FROM pgv_stats() ORDER BY package;
  package | used_memory
 ---------+-------------
  vars    |       16736
@@ -625,14 +638,14 @@ SELECT * FROM pgv_stats() order by package;
       You can delete variables or whole packages:
     </para>
 <programlisting>
-SELECT pgv_remove('vars', 'int1');
-SELECT pgv_remove('vars');
+postgres=# SELECT pgv_remove('vars', 'int1');
+postgres=# SELECT pgv_remove('vars');
 </programlisting>
     <para>
       You can delete all packages and variables:
     </para>
 <programlisting>
-SELECT pgv_free();
+postgres=# SELECT pgv_free();
 </programlisting>
   </sect2>
 </sect1>