Add mention of TOAST storage for character columns.

diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index 573fe75f3628f8eb89669c147ae1b9a33c5f8c2b..d805439d830f69bb6fe2045b2f99c612392301fd 100644 (file)
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -1,5 +1,5 @@
 
 
  
@@ -843,19 +843,20 @@ CREATE TABLE tablename (
    
 
    
-    The storage requirement for data of these types is 4 bytes plus
-    the actual string, and in case of character plus the
-    padding.  Long strings will be compressed by the system
-    automatically, so the physical requirement on disk may be less.
-    In any case, the longest possible character string
-    that can be stored is about 1 GB.  (The maximum value that will be
-    allowed for n in the data type declaration is
-    less than that.  It wouldn't be very useful to change
-    this because with multibyte character encodings the number of
-    characters and bytes can be quite different anyway.  If you desire
-    to store long strings with no specific upper limit, use text
-    or character varying without a length specifier,
-    rather than making up an arbitrary length limit.)
+    The storage requirement for data of these types is 4 bytes plus the
+    actual string, and in case of character plus the
+    padding. Long strings are compressed by the system automatically, so
+    the physical requirement on disk may be less. Long values are also
+    stored in background tables so they don't interfere with rapid
+    access to the shorter column values. In any case, the longest
+    possible character string that can be stored is about 1 GB. (The
+    maximum value that will be allowed for n in the data
+    type declaration is less than that. It wouldn't be very useful to
+    change this because with multibyte character encodings the number of
+    characters and bytes can be quite different anyway. If you desire to
+    store long strings with no specific upper limit, use
+    text or character varying without a length
+    specifier, rather than making up an arbitrary length limit.)