doc: Document that sequences can also be extension configuration tables

From: Michael Paquier 

diff --git a/doc/src/sgml/extend.sgml b/doc/src/sgml/extend.sgml
index df3b9d9cb22e12191c6cc2c9d3b976878330ca95..f050ff1f6601773cad9589f3f2715d2d822b3b54 100644 (file)
--- a/doc/src/sgml/extend.sgml
+++ b/doc/src/sgml/extend.sgml
@@ -698,17 +698,21 @@ SET LOCAL search_path TO @extschema@;
 
     
      To solve this problem, an extension's script file can mark a table
-     it has created as a configuration table, which will cause
-     pg_dump to include the table's contents (not its
-     definition) in dumps.  To do that, call the function
+     or a sequence it has created as a configuration relation, which will
+     cause pg_dump to include the table's or the sequence's
+     contents (not its definition) in dumps.  To do that, call the function
      pg_extension_config_dump(regclass, text) after creating the
-     table, for example
+     table or the sequence, for example
 
 CREATE TABLE my_config (key text, value text);
+CREATE SEQUENCE my_config_seq;
 
 SELECT pg_catalog.pg_extension_config_dump('my_config', '');
+SELECT pg_catalog.pg_extension_config_dump('my_config_seq', '');
 
-     Any number of tables can be marked this way.
+     Any number of tables or sequences can be marked this way. Sequences
+     associated with serial or bigserial columns can
+     be marked as well.
     
 
     
@@ -729,6 +733,11 @@ SELECT pg_catalog.pg_extension_config_dump('my_config', 'WHERE NOT standard_entr
      in the rows created by the extension's script.
     
 
+    
+     For sequences, the second argument of pg_extension_config_dump
+     has no effect.
+    
+
     
      More complicated situations, such as initially-provided rows that might
      be modified by users, can be handled by creating triggers on the
@@ -753,6 +762,12 @@ SELECT pg_catalog.pg_extension_config_dump('my_config', 'WHERE NOT standard_entr
      out but the dump will not be able to be restored directly and user
      intervention will be required.
     
+    
+    
+     Sequences associated with serial or bigserial columns
+     need to be directly marked to dump their state. Marking their parent
+     relation is not enough for this purpose.
+