Provide a concrete example of parameter expansion in archive_command.

Per discussion of bug #3877.  Simon Riggs, some fixes by moi.

diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgml
index 7cae1424795a069b1d848fb6429b253ed823c690..6252159025fd9fa8b21dbc97a9a4786ba8b248e3 100644 (file)
--- a/doc/src/sgml/backup.sgml
+++ b/doc/src/sgml/backup.sgml
@@ -1,4 +1,4 @@
-
+
 
 
  Backup and Restore
@@ -64,7 +64,7 @@ pg_dump dbname > 
   
 
   
-   As any other PostgreSQL client application,
+   Like any other PostgreSQL client application,
    pg_dump will by default connect with the database
    user name that is equal to the current operating system user name. To override
    this, either specify the -U option or set the
@@ -407,7 +407,7 @@ tar -cf backup.tar /usr/local/pgsql/data
    smaller than an SQL dump. On the contrary, it will most likely be
    larger. (pg_dump does not need to dump
    the contents of indexes for example, just the commands to recreate
-   them.)
+   them.)  However, taking a file system backup might be faster.
   
  
 
@@ -556,7 +556,13 @@ archive_command = 'cp -i %p /mnt/server/archivedir/%f </dev/null'
 
     which will copy archivable WAL segments to the directory
     /mnt/server/archivedir.  (This is an example, not a
-    recommendation, and might not work on all platforms.)
+    recommendation, and might not work on all platforms.)  After the
+    %p and %f parameters have been replaced,
+    the actual command executed might look like this:
+
+cp -i pg_xlog/00000001000000A900000065 /mnt/server/archivedir/00000001000000A900000065 </dev/null
+
+    A similar command will be generated for each new file to be archived.