From b73ecebf05041ab8643d6a4808ab807fb44f00b0 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 30 Nov 2000 18:46:42 +0000
Subject: [PATCH] Remove obsolete claim that char(n) is more efficient than
other text types.
---
doc/FAQ | 14 ++++++--------
doc/src/FAQ/FAQ.html | 20 +++++++++-----------
2 files changed, 15 insertions(+), 19 deletions(-)
diff --git a/doc/FAQ b/doc/FAQ
index 403808f7bff..11a4783ab87 100644
--- a/doc/FAQ
+++ b/doc/FAQ
@@ -811,19 +811,17 @@ Type Internal Name Notes
"char" char 1 character
CHAR(#) bpchar blank padded to the specified fixed length
VARCHAR(#) varchar size specifies maximum length, no padding
-TEXT text length limited only by maximum row length
-BYTEA bytea variable-length array of bytes
+TEXT text no specific upper limit on length
+BYTEA bytea variable-length byte array (null-safe)
You will see the internal name when examining system catalogs and in
some error messages.
The last four types above are "varlena" types (i.e., the first four
- bytes are the length, followed by the data). char(#) allocates the
- maximum number of bytes no matter how much data is stored in the
- field. text, varchar(#), and bytea all have variable length on the
- disk, and because of this, there is a small performance penalty for
- using them. Specifically, the penalty is for access to all columns
- after the first column of this type.
+ bytes on disk are the length, followed by the data). Thus the actual
+ space used is slightly greater than the declared size. However, these
+ data types are also subject to compression or being stored out-of-line
+ by TOAST, so the space on disk might also be less than expected.
4.16.1) How do I create a serial/auto-incrementing field?
diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html
index 585807e6ab9..1123086be9a 100644
--- a/doc/src/FAQ/FAQ.html
+++ b/doc/src/FAQ/FAQ.html
@@ -534,7 +534,7 @@ A report generator? An embedded query language interface?</H4><P>
We have a nice graphical user interface called <I>pgaccess,</I> which is
shipped as part of the distribution. <I>Pgaccess</I> also has a report
-generator. The Web page is <A HREF=
+generator. The Web page is <A HREF=""
"http://www.flex.ro/pgaccess">http://www.flex.ro/pgaccess</A><P>
We also include <I>ecpg,</I> which is an embedded SQL query language interface for
@@ -996,20 +996,18 @@ Type Internal Name Notes
"char" char 1 character
CHAR(#) bpchar blank padded to the specified fixed length
VARCHAR(#) varchar size specifies maximum length, no padding
-TEXT text length limited only by maximum row length
-BYTEA bytea variable-length array of bytes
+TEXT text no specific upper limit on length
+BYTEA bytea variable-length byte array (null-safe)
</PRE><P>
You will see the internal name when examining system catalogs
and in some error messages.<P>
-
-The last four types above are "varlena" types (i.e., the first four bytes
-are the length, followed by the data). <I>char(#)</I> allocates the
-maximum number of bytes no matter how much data is stored in the field.
-<I>text, varchar(#),</I> and <I>bytea</I> all have variable length on the disk,
-and because of this, there is a small performance penalty for using
-them. Specifically, the penalty is for access to all columns after the
-first column of this type.<P>
+
+The last four types above are "varlena" types (i.e., the first four
+bytes on disk are the length, followed by the data). Thus the actual
+space used is slightly greater than the declared size. However, these
+data types are also subject to compression or being stored out-of-line
+by TOAST, so the space on disk might also be less than expected.<P>
<H4><A NAME="4.16.1">4.16.1</A>) How do I create a
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