Rearrange documentation paragraph describing pg_relation_size().

Break the list of available options into an  instead of
inline sentences.  This is mostly motivated by wanting to ensure that the
cross-references to the FSM and VM docs don't cross page boundaries in PDF
format; but it seems to me to read more easily this way anyway.  I took the
liberty of editorializing a bit further while at it.

Per complaint from Magnus about 9.0.18 docs not building in A4 format.
Patch all active branches so we don't get blind-sided by this particular
issue again in future.

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 3c7cf7b5e63cfde374fe2ac1494a520b1c68073f..86d3a917b9240f90e891c312f81ef874e9ad41bf 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15703,18 +15703,34 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
    
 
    
-    pg_relation_size accepts the OID or name of a table, index or
-    toast table, and returns the on-disk size in bytes. Specifying
-    'main' or leaving out the second argument returns the
-    size of the main data fork of the relation. Specifying
-    'fsm' returns the size of the
-    Free Space Map (see ) associated with the
-    relation. Specifying 'vm' returns the size of the
-    Visibility Map (see ) associated with the
-    relation.  Note that this function shows the size of only one fork;
-    for most purposes it is more convenient to use the higher-level
-    functions pg_total_relation_size or
-    pg_table_size.
+    pg_relation_size accepts the OID or name of a table, index
+    or toast table, and returns the on-disk size in bytes of one fork of
+    that relation.  (Note that for most purposes it is more convenient to
+    use the higher-level functions pg_total_relation_size
+    or pg_table_size, which sum the sizes of all forks.)
+    With one argument, it returns the size of the main data fork of the
+    relation.  The second argument can be provided to specify which fork
+    to examine:
+    
+     
+      
+       'main' returns the size of the main
+       data fork of the relation.
+      
+     
+     
+      
+       'fsm' returns the size of the Free Space Map
+       (see ) associated with the relation.
+      
+     
+     
+      
+       'vm' returns the size of the Visibility Map
+       (see ) associated with the relation.
+      
+     
+