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authorBruce Momjian <bruce@momjian.us>2002-07-16 04:45:59 +0000
committerBruce Momjian <bruce@momjian.us>2002-07-16 04:45:59 +0000
commitd76eef3e7cca5165941a5ef08e71f6a7c722b7bd (patch)
tree7bb0a862abbcead71940aad70c64477ba61495cb
parentb3341ddbf2f4e849d770aa8682fedbf0a74a2980 (diff)
downloadpostgresql-d76eef3e7cca5165941a5ef08e71f6a7c722b7bd.tar.gz
postgresql-d76eef3e7cca5165941a5ef08e71f6a7c722b7bd.zip
Add mention of TOAST storage for character columns.
-rw-r--r--doc/src/sgml/datatype.sgml29
1 files changed, 15 insertions, 14 deletions
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index 573fe75f362..d805439d830 100644
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -1,5 +1,5 @@
<!--
-$Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.94 2002/07/16 03:30:26 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.95 2002/07/16 04:45:59 momjian Exp $
-->
<chapter id="datatype">
@@ -843,19 +843,20 @@ CREATE TABLE <replaceable class="parameter">tablename</replaceable> (<replaceabl
</para>
<para>
- The storage requirement for data of these types is 4 bytes plus
- the actual string, and in case of <type>character</type> 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 <replaceable>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 <type>text</type>
- or <type>character varying</type> 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 <type>character</type> 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 <replaceable>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
+ <type>text</type> or <type>character varying</type> without a length
+ specifier, rather than making up an arbitrary length limit.)
</para>
<tip>