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From j..@apache.org
Subject svn commit: r149319 - in incubator/derby/site/trunk: build/site/ build/site/papers/ src/documentation/content/xdocs/ src/documentation/content/xdocs/papers/
Date Mon, 31 Jan 2005 23:13:42 GMT
Author: jta
Date: Mon Jan 31 15:13:36 2005
New Revision: 149319

URL: http://svn.apache.org/viewcvs?view=rev&rev=149319
Log:
Added Dibyendu Majumdar <dibyendu@mazumdar.demon.co.uk> document on
"Derby On Disk Page Format".
Modified faq.html#createdb_OS_X to clarify that this issue also applies to 
modifying an existing database.

Added:
    incubator/derby/site/trunk/build/site/papers/alloc-page.png   (with props)
    incubator/derby/site/trunk/build/site/papers/field-header-non-overflow.png   (with props)
    incubator/derby/site/trunk/build/site/papers/field-header-overflow.png   (with props)
    incubator/derby/site/trunk/build/site/papers/page-format.png   (with props)
    incubator/derby/site/trunk/build/site/papers/pageformats.html
    incubator/derby/site/trunk/src/documentation/content/xdocs/papers/alloc-page.aart
    incubator/derby/site/trunk/src/documentation/content/xdocs/papers/field-header-non-overflow.aart
    incubator/derby/site/trunk/src/documentation/content/xdocs/papers/field-header-overflow.aart
    incubator/derby/site/trunk/src/documentation/content/xdocs/papers/page-format.aart
    incubator/derby/site/trunk/src/documentation/content/xdocs/papers/pageformats.xml
Modified:
    incubator/derby/site/trunk/build/site/faq.html
    incubator/derby/site/trunk/build/site/linkmap.html
    incubator/derby/site/trunk/build/site/papers/ApacheConUs04.html
    incubator/derby/site/trunk/build/site/papers/JDBCImplementation.html
    incubator/derby/site/trunk/build/site/papers/MiscPresentations.html
    incubator/derby/site/trunk/build/site/papers/derby_arch.html
    incubator/derby/site/trunk/build/site/papers/derby_htw.html
    incubator/derby/site/trunk/build/site/papers/derby_plugin.html
    incubator/derby/site/trunk/build/site/papers/derby_web.html
    incubator/derby/site/trunk/build/site/papers/fortune_tut.html
    incubator/derby/site/trunk/build/site/papers/index.html
    incubator/derby/site/trunk/build/site/papers/misc.html
    incubator/derby/site/trunk/src/documentation/content/xdocs/faq.xml
    incubator/derby/site/trunk/src/documentation/content/xdocs/papers/index.xml
    incubator/derby/site/trunk/src/documentation/content/xdocs/site.xml

Modified: incubator/derby/site/trunk/build/site/faq.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/faq.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/faq.html (original)
+++ incubator/derby/site/trunk/build/site/faq.html Mon Jan 31 15:13:36 2005
@@ -203,7 +203,8 @@
 <ul class="minitoc">
 <li>
 <a href="#createdb_OS_X">2.1. 
-        Why can't I create a new database on Mac OS X?
+        Why can't I create a new database or modify an existing database 
+	on Mac OS X?
       </a>
 </li>
 <li>
@@ -339,7 +340,8 @@
 <h3 class="boxed">2. Using Derby</h3>
 <a name="N1005C"></a><a name="createdb_OS_X"></a>
 <h4 class="faq">2.1. 
-        Why can't I create a new database on Mac OS X?
+        Why can't I create a new database or modify an existing database 
+	on Mac OS X?
       </h4>
 <div align="right">
 <a href="#createdb_OS_X-menu">^</a>

Modified: incubator/derby/site/trunk/build/site/linkmap.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/linkmap.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/linkmap.html (original)
+++ incubator/derby/site/trunk/build/site/linkmap.html Mon Jan 31 15:13:36 2005
@@ -156,6 +156,9 @@
 <a title="" href="papers/derby_arch.html">Architecture</a>
 </div>
 <div class="menuitem">
+<a title="" href="papers/pageformats.html">Disk Page Format</a>
+</div>
+<div class="menuitem">
 <a title="" href="papers/derby_htw.html">How Things Work</a>
 </div>
 <div class="menuitem">
@@ -379,6 +382,10 @@
       
 <li>
 <a href="papers/derby_arch.html">Architecture</a>&nbsp;&nbsp;&nbsp;_________________________&nbsp;&nbsp;<em>index</em>
+</li>
+      
+<li>
+<a href="papers/pageformats.html">Disk Page Format</a>&nbsp;&nbsp;&nbsp;_________________________&nbsp;&nbsp;<em>pformat</em>
 </li>
       
 <li>

Modified: incubator/derby/site/trunk/build/site/papers/ApacheConUs04.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/ApacheConUs04.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/ApacheConUs04.html (original)
+++ incubator/derby/site/trunk/build/site/papers/ApacheConUs04.html Mon Jan 31 15:13:36 2005
@@ -117,6 +117,9 @@
 <a title="" href="../papers/derby_arch.html">Architecture</a>
 </div>
 <div class="menuitem">
+<a title="" href="../papers/pageformats.html">Disk Page Format</a>
+</div>
+<div class="menuitem">
 <a title="" href="../papers/derby_htw.html">How Things Work</a>
 </div>
 <div class="menuitem">

Modified: incubator/derby/site/trunk/build/site/papers/JDBCImplementation.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/JDBCImplementation.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/JDBCImplementation.html (original)
+++ incubator/derby/site/trunk/build/site/papers/JDBCImplementation.html Mon Jan 31 15:13:36 2005
@@ -117,6 +117,9 @@
 <a title="" href="../papers/derby_arch.html">Architecture</a>
 </div>
 <div class="menuitem">
+<a title="" href="../papers/pageformats.html">Disk Page Format</a>
+</div>
+<div class="menuitem">
 <a title="" href="../papers/derby_htw.html">How Things Work</a>
 </div>
 <div class="menupage">

Modified: incubator/derby/site/trunk/build/site/papers/MiscPresentations.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/MiscPresentations.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/MiscPresentations.html (original)
+++ incubator/derby/site/trunk/build/site/papers/MiscPresentations.html Mon Jan 31 15:13:36 2005
@@ -117,6 +117,9 @@
 <a title="" href="../papers/derby_arch.html">Architecture</a>
 </div>
 <div class="menuitem">
+<a title="" href="../papers/pageformats.html">Disk Page Format</a>
+</div>
+<div class="menuitem">
 <a title="" href="../papers/derby_htw.html">How Things Work</a>
 </div>
 <div class="menuitem">

Added: incubator/derby/site/trunk/build/site/papers/alloc-page.png
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/alloc-page.png?view=auto&rev=149319
==============================================================================
Binary file - no diff available.

Propchange: incubator/derby/site/trunk/build/site/papers/alloc-page.png
------------------------------------------------------------------------------
    svn:mime-type = application/octet-stream

Modified: incubator/derby/site/trunk/build/site/papers/derby_arch.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/derby_arch.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/derby_arch.html (original)
+++ incubator/derby/site/trunk/build/site/papers/derby_arch.html Mon Jan 31 15:13:36 2005
@@ -117,6 +117,9 @@
 <div class="menupagetitle">Architecture</div>
 </div>
 <div class="menuitem">
+<a title="" href="../papers/pageformats.html">Disk Page Format</a>
+</div>
+<div class="menuitem">
 <a title="" href="../papers/derby_htw.html">How Things Work</a>
 </div>
 <div class="menuitem">

Modified: incubator/derby/site/trunk/build/site/papers/derby_htw.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/derby_htw.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/derby_htw.html (original)
+++ incubator/derby/site/trunk/build/site/papers/derby_htw.html Mon Jan 31 15:13:36 2005
@@ -116,6 +116,9 @@
 <div class="menuitem">
 <a title="" href="../papers/derby_arch.html">Architecture</a>
 </div>
+<div class="menuitem">
+<a title="" href="../papers/pageformats.html">Disk Page Format</a>
+</div>
 <div class="menupage">
 <div class="menupagetitle">How Things Work</div>
 </div>

Modified: incubator/derby/site/trunk/build/site/papers/derby_plugin.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/derby_plugin.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/derby_plugin.html (original)
+++ incubator/derby/site/trunk/build/site/papers/derby_plugin.html Mon Jan 31 15:13:36 2005
@@ -117,6 +117,9 @@
 <a title="" href="../papers/derby_arch.html">Architecture</a>
 </div>
 <div class="menuitem">
+<a title="" href="../papers/pageformats.html">Disk Page Format</a>
+</div>
+<div class="menuitem">
 <a title="" href="../papers/derby_htw.html">How Things Work</a>
 </div>
 <div class="menuitem">

Modified: incubator/derby/site/trunk/build/site/papers/derby_web.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/derby_web.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/derby_web.html (original)
+++ incubator/derby/site/trunk/build/site/papers/derby_web.html Mon Jan 31 15:13:36 2005
@@ -117,6 +117,9 @@
 <a title="" href="../papers/derby_arch.html">Architecture</a>
 </div>
 <div class="menuitem">
+<a title="" href="../papers/pageformats.html">Disk Page Format</a>
+</div>
+<div class="menuitem">
 <a title="" href="../papers/derby_htw.html">How Things Work</a>
 </div>
 <div class="menuitem">

Added: incubator/derby/site/trunk/build/site/papers/field-header-non-overflow.png
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/field-header-non-overflow.png?view=auto&rev=149319
==============================================================================
Binary file - no diff available.

Propchange: incubator/derby/site/trunk/build/site/papers/field-header-non-overflow.png
------------------------------------------------------------------------------
    svn:mime-type = application/octet-stream

Added: incubator/derby/site/trunk/build/site/papers/field-header-overflow.png
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/field-header-overflow.png?view=auto&rev=149319
==============================================================================
Binary file - no diff available.

Propchange: incubator/derby/site/trunk/build/site/papers/field-header-overflow.png
------------------------------------------------------------------------------
    svn:mime-type = application/octet-stream

Modified: incubator/derby/site/trunk/build/site/papers/fortune_tut.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/fortune_tut.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/fortune_tut.html (original)
+++ incubator/derby/site/trunk/build/site/papers/fortune_tut.html Mon Jan 31 15:13:36 2005
@@ -117,6 +117,9 @@
 <a title="" href="../papers/derby_arch.html">Architecture</a>
 </div>
 <div class="menuitem">
+<a title="" href="../papers/pageformats.html">Disk Page Format</a>
+</div>
+<div class="menuitem">
 <a title="" href="../papers/derby_htw.html">How Things Work</a>
 </div>
 <div class="menuitem">

Modified: incubator/derby/site/trunk/build/site/papers/index.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/index.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/index.html (original)
+++ incubator/derby/site/trunk/build/site/papers/index.html Mon Jan 31 15:13:36 2005
@@ -117,6 +117,9 @@
 <a title="" href="../papers/derby_arch.html">Architecture</a>
 </div>
 <div class="menuitem">
+<a title="" href="../papers/pageformats.html">Disk Page Format</a>
+</div>
+<div class="menuitem">
 <a title="" href="../papers/derby_htw.html">How Things Work</a>
 </div>
 <div class="menuitem">
@@ -220,6 +223,9 @@
 	 Overview</a>
 </li>
         
+<li>Disk Page Format:<a href="pageformats.html">Derby On Disk Page Format</a>
+</li>
+        
 <li>
 <a href="derby_htw.html">How Things Work</a> 
 </li> 
@@ -232,7 +238,7 @@
 </div>
 
 
-<a name="N1002E"></a><a name="Integration"></a>
+<a name="N10034"></a><a name="Integration"></a>
 <h2 class="boxed">Integration</h2>
 <div class="section">
 <p>  The <a href="misc.html">Summary</a> contains pointers
@@ -264,7 +270,7 @@
 </div>
 
 
-<a name="N10065"></a><a name="Presentations"></a>
+<a name="N1006B"></a><a name="Presentations"></a>
 <h2 class="boxed">Presentations</h2>
 <div class="section">
 <ul>
@@ -323,7 +329,7 @@
 </div>
 
 
-<a name="N100CB"></a><a name="How+To%27s"></a>
+<a name="N100D1"></a><a name="How+To%27s"></a>
 <h2 class="boxed">How To's</h2>
 <div class="section">
 <p>
@@ -335,7 +341,7 @@
 </div>
 
 
-<a name="N100D9"></a><a name="How+to+Contribute+Papers"></a>
+<a name="N100DF"></a><a name="How+to+Contribute+Papers"></a>
 <h2 class="boxed">How to Contribute Papers</h2>
 <div class="section">
 <p>
@@ -408,7 +414,7 @@
 
 
 <p>
-<em>Last Updated: January 21, 2005</em>
+<em>Last Updated: January 31, 2005</em>
 </p>
 
 </div>

Modified: incubator/derby/site/trunk/build/site/papers/misc.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/misc.html?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/misc.html (original)
+++ incubator/derby/site/trunk/build/site/papers/misc.html Mon Jan 31 15:13:36 2005
@@ -117,6 +117,9 @@
 <a title="" href="../papers/derby_arch.html">Architecture</a>
 </div>
 <div class="menuitem">
+<a title="" href="../papers/pageformats.html">Disk Page Format</a>
+</div>
+<div class="menuitem">
 <a title="" href="../papers/derby_htw.html">How Things Work</a>
 </div>
 <div class="menuitem">

Added: incubator/derby/site/trunk/build/site/papers/page-format.png
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/page-format.png?view=auto&rev=149319
==============================================================================
Binary file - no diff available.

Propchange: incubator/derby/site/trunk/build/site/papers/page-format.png
------------------------------------------------------------------------------
    svn:mime-type = application/octet-stream

Added: incubator/derby/site/trunk/build/site/papers/pageformats.html
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/build/site/papers/pageformats.html?view=auto&rev=149319
==============================================================================
--- incubator/derby/site/trunk/build/site/papers/pageformats.html (added)
+++ incubator/derby/site/trunk/build/site/papers/pageformats.html Mon Jan 31 15:13:36 2005
@@ -0,0 +1,760 @@
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
+<html>
+<head>
+<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
+<meta content="Apache Forrest" name="Generator">
+<meta name="Forrest-version" content="0.6">
+<meta name="Forrest-skin-name" content="pelt">
+<title>Derby On Disk Page Format</title>
+<link type="text/css" href="../skin/basic.css" rel="stylesheet">
+<link media="screen" type="text/css" href="../skin/screen.css" rel="stylesheet">
+<link media="print" type="text/css" href="../skin/print.css" rel="stylesheet">
+<link type="text/css" href="../skin/profile.css" rel="stylesheet">
+<script src="../skin/getBlank.js" language="javascript" type="text/javascript"></script><script src="../skin/getMenu.js" language="javascript" type="text/javascript"></script><script src="../skin/fontsize.js" language="javascript" type="text/javascript"></script>
+<link rel="shortcut icon" href="../">
+</head>
+<body onload="init()">
+<script type="text/javascript">ndeSetTextSize();</script>
+<div id="top">
+<!--+
+    |breadtrail
+    +-->
+<div class="breadtrail">
+<a href="http://www.apache.org/">apache</a> &gt; <a href="http://incubator.apache.org/">incubator</a><script src="../skin/breadcrumbs.js" language="JavaScript" type="text/javascript"></script>
+</div>
+<!--+
+    |header
+    +-->
+<div class="header">
+<!--+
+    |start group logo
+    +-->
+<div class="grouplogo">
+<a href="http://incubator.apache.org"><img class="logoImage" alt="" src="../images/apache-incubator-logo.png" title=""></a>
+</div>
+<!--+
+    |end group logo
+    +-->
+<!--+
+    |start Project Logo
+    +-->
+<div class="projectlogo">
+<a href="http://incubator.apache.org/derby/"><img class="logoImage" alt="Derby" src="../images/derby-logo.jpg" title="Derby is a zero admin java RDBMS."></a>
+</div>
+<!--+
+    |end Project Logo
+    +-->
+<!--+
+    |start Search
+    +-->
+<div class="searchbox">
+<form action="http://www.google.com/search" method="get" class="roundtopsmall">
+<input value="apache.org" name="sitesearch" type="hidden"><input onFocus="getBlank (this, 'Search the site with google:');" value="Search the site with google:" size="25" name="q" id="query" type="text">&nbsp; 
+                    <input name="Search" value="Search" type="submit">
+</form>
+</div>
+<!--+
+    |end search
+    +-->
+<!--+
+    |start Tabs
+    +-->
+<ul id="tabs">
+<li>
+<a class="base-not-selected" href="../index.html">Home</a>
+</li>
+<li>
+<a class="base-not-selected" href="../manuals/index.html">Manuals</a>
+</li>
+<li class="current">
+<a class="base-selected" href="../papers/index.html">Papers</a>
+</li>
+</ul>
+<!--+
+    |end Tabs
+    +-->
+</div>
+</div>
+<div id="main">
+<div id="publishedStrip">
+<!--+
+    |start Subtabs
+    +-->
+<div id="level2tabs"></div>
+<!--+
+    |end Endtabs
+    +-->
+<script type="text/javascript" language="JavaScript"><!--
+              document.write("Published: " + document.lastModified);
+              //  --></script>
+</div>
+<!--+
+    |breadtrail
+    +-->
+<div class="breadtrail">
+             
+             &nbsp;
+           </div>
+<!--+
+    |start Menu, mainarea
+    +-->
+<!--+
+    |start Menu
+    +-->
+<div id="menu">
+<div onclick="SwitchMenu('menu_1.1', '../skin/')" id="menu_1.1Title" class="menutitle">About</div>
+<div id="menu_1.1" class="menuitemgroup">
+<div class="menuitem">
+<a title="" href="../papers/index.html">Index</a>
+</div>
+<div class="menuitem">
+<a title="" href="../papers/derby_web.html">Derby Web Site</a>
+</div>
+</div>
+<div onclick="SwitchMenu('menu_selected_1.2', '../skin/')" id="menu_selected_1.2Title" class="menutitle" style="background-image: url('../skin/images/chapter_open.gif');">Derby Engine</div>
+<div id="menu_selected_1.2" class="selectedmenuitemgroup" style="display: block;">
+<div class="menuitem">
+<a title="" href="../papers/derby_arch.html">Architecture</a>
+</div>
+<div class="menupage">
+<div class="menupagetitle">Disk Page Format</div>
+</div>
+<div class="menuitem">
+<a title="" href="../papers/derby_htw.html">How Things Work</a>
+</div>
+<div class="menuitem">
+<a title="" href="../papers/JDBCImplementation.html">JDBC</a>
+</div>
+</div>
+<div onclick="SwitchMenu('menu_1.3', '../skin/')" id="menu_1.3Title" class="menutitle">Integration</div>
+<div id="menu_1.3" class="menuitemgroup">
+<div class="menuitem">
+<a title="" href="../papers/misc.html">Summary</a>
+</div>
+<div class="menuitem">
+<a title="" href="../binaries/HOWTO_CJDBC_Derby_v0.2.pdf">C-JDBC (PDF)</a>
+</div>
+<div class="menuitem">
+<a title="" href="../binaries/HOWTO_CJDBC_Derby_v0.2.sxw">C-JDBC (SXW)</a>
+</div>
+<div class="menuitem">
+<a title="" href="../DOTS_Derby.html">DOTS</a>
+</div>
+<div class="menuitem">
+<a title="" href="../papers/derby_plugin.html">Eclipse</a>
+</div>
+<div class="menuitem">
+<a title="" href="../binaries/DerbyAndRedHatAppServer.pdf">JOnAS (PDF)</a>
+</div>
+</div>
+<div onclick="SwitchMenu('menu_1.4', '../skin/')" id="menu_1.4Title" class="menutitle">Presentations</div>
+<div id="menu_1.4" class="menuitemgroup">
+<div class="menuitem">
+<a title="" href="../papers/MiscPresentations.html">Colorado 2004</a>
+</div>
+<div class="menuitem">
+<a title="" href="../papers/ApacheConUs04.html">ApacheCon US '04</a>
+</div>
+</div>
+<div onclick="SwitchMenu('menu_1.5', '../skin/')" id="menu_1.5Title" class="menutitle">How To's</div>
+<div id="menu_1.5" class="menuitemgroup">
+<div class="menuitem">
+<a title="" href="../papers/fortune_tut.html">Embedded Tutorial</a>
+</div>
+</div>
+<div id="credit"></div>
+<div id="roundbottom">
+<img style="display: none" class="corner" height="15" width="15" alt="" src="../skin/images/rc-b-l-15-1body-2menu-3menu.png"></div>
+<!--+
+  |alternative credits
+  +-->
+</div>
+<!--+
+    |end Menu
+    +-->
+<!--+
+    |start content
+    +-->
+<div id="content">
+<div id="skinconf-txtlink"></div>
+<div class="trail">
+	        Font size: 
+	          &nbsp;<input value="Reset" class="resetfont" title="Reset text" onclick="ndeSetTextSize('reset'); return false;" type="button">      
+	          &nbsp;<input value="-a" class="smallerfont" title="Shrink text" onclick="ndeSetTextSize('decr'); return false;" type="button">
+	          &nbsp;<input value="+a" class="biggerfont" title="Enlarge text" onclick="ndeSetTextSize('incr'); return false;" type="button">
+</div>
+<h1>Derby On Disk Page Format</h1>
+<div class="abstract">This document describes the storage format of Derby disk pages. 
+    This is a work-in-progress derived from Javadoc comments and 
+    from explanations Mike Matrigali posted to the Derby lists. 
+    Please post questions, comments, and corrections to 
+    derby-dev@db.apache.org.
+    </div>
+<div id="minitoc-area">
+<ul class="minitoc">
+<li>
+<a href="#introduction"> Introduction </a>
+</li>
+<li>
+<a href="#storedpage">Data Page Format</a>
+<ul class="minitoc">
+<li>
+<a href="#formatid">Format Id </a>
+</li>
+<li>
+<a href="#pageheader"> Page Header </a>
+</li>
+<li>
+<a href="#records"> Records </a>
+</li>
+<li>
+<a href="#slottable">Slot Offset Table</a>
+</li>
+<li>
+<a href="#checksum">Checksum</a>
+</li>
+</ul>
+</li>
+<li>
+<a href="#allocpage">Allocation Page</a>
+</li>
+</ul>
+</div>
+
+
+    
+<a name="N1000F"></a><a name="introduction"></a>
+<h2 class="boxed"> Introduction </h2>
+<div class="section">
+<p>Derby stores table and index data in Containers, which currently map 
+        to files in the 
+        <span class="codefrag">seg0</span>
+        directory of the database. Data is stored in pages within the container.</p>
+<div class="frame fixme">
+<div class="label">Fixme (Dibyendu Majumdar)</div>
+<div class="content"> Do all containers map to a single file, or does each container map 
+        to a file? </div>
+</div>
+<p>A page contains a set of records, which can be accessed by "slot", which 
+        defines the order of the records on the page, or by "id" which defines 
+        the identity of the records on the page. Clients access records by both 
+        slot and id, depending on their needs.</p>
+<p>There are two types of pages - Raw Stored Pages which hold data, and 
+        Raw Stored Alloc Pages which hold page allocation information.</p>
+<p>A Table or a BTree index provides a row-based access mechanism (row-based 
+        access interface is known as conglomerate). Rows are mapped to records 
+        in pages, in case of a table, a single row can span multiple records in 
+        multiple pages.</p>
+</div>
+    
+<a name="N10029"></a><a name="storedpage"></a>
+<h2 class="boxed">Data Page Format</h2>
+<div class="section">
+<p>A data page is broken into five sections. 
+        <img alt="" src="page-format.png">
+      </p>
+<a name="N10036"></a><a name="formatid"></a>
+<h3 class="boxed">Format Id </h3>
+<p> The formatId is a 4 bytes array, it contains the format Id of this 
+          page. The possible values are RAW_STORE_STORED_PAGE or RAW_STORE_ALLOC_PAGE.</p>
+<a name="N10040"></a><a name="pageheader"></a>
+<h3 class="boxed"> Page Header </h3>
+<p> The page header is a fixed size, 56 bytes. </p>
+<table class="ForrestTable" cellspacing="1" cellpadding="4"> 
+            
+<tr> 
+              
+<th colspan="1" rowspan="1">Size</th>
+              <th colspan="1" rowspan="1">Type</th>
+              <th colspan="1" rowspan="1">Description</th>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">1 byte</td>
+              <td colspan="1" rowspan="1">boolean</td>
+              <td colspan="1" rowspan="1">is page an overflow page</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">1 byte</td>
+              <td colspan="1" rowspan="1">byte</td>
+              <td colspan="1" rowspan="1">
+<p>page status is either VALID_PAGE or INVALID_PAGE(a field 
+                  maintained in base page)</p>
+                
+<p>page goes thru the following transition: 
+                  <br>
+                  VALID_PAGE &lt;-&gt; deallocated page -&gt; free page &lt;-&gt; 
+                  VALID_PAGE</p>
+                
+<p>deallocated and free page are both INVALID_PAGE as far as BasePage 
+                  is concerned. 
+                  <br>
+                  When a page is deallocated, it transitioned from VALID_PAGE 
+                  to INVALID_PAGE. 
+                  <br>
+                  When a page is allocated, it trnasitioned from INVALID_PAGE 
+                  to VALID_PAGE.</p>
+</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">8 bytes</td>
+              <td colspan="1" rowspan="1">long</td>
+              <td colspan="1" rowspan="1">pageVersion (a field maintained in base page)</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">2 bytes</td>
+              <td colspan="1" rowspan="1">unsigned short</td>
+              <td colspan="1" rowspan="1">number of slots in slot offset table</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">4 bytes</td>
+              <td colspan="1" rowspan="1">integer</td>
+              <td colspan="1" rowspan="1">next record identifier</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">4 bytes</td>
+              <td colspan="1" rowspan="1">integer</td>
+              <td colspan="1" rowspan="1">generation number of this page (Future Use)</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">4 bytes</td>
+              <td colspan="1" rowspan="1">integer</td>
+              <td colspan="1" rowspan="1">previous generation of this page (Future Use)</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">8 bytes</td>
+              <td colspan="1" rowspan="1">bipLocation</td>
+              <td colspan="1" rowspan="1">the location of the beforeimage page (Future Use)</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">2 bytes</td>
+              <td colspan="1" rowspan="1">unsigned short</td>
+              <td colspan="1" rowspan="1">number of deleted rows on page. (new release 2.0)</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">2 bytes</td>
+              <td colspan="1" rowspan="1">unsigned short</td>
+              <td colspan="1" rowspan="1">% of the page to keep free for updates</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">2 bytes</td>
+              <td colspan="1" rowspan="1">short</td>
+              <td colspan="1" rowspan="1">spare for future use</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">4 bytes</td>
+              <td colspan="1" rowspan="1">long</td>
+              <td colspan="1" rowspan="1">spare for future use (encryption uses to write random bytes 
+                here).</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">8 bytes</td>
+              <td colspan="1" rowspan="1">long</td>
+              <td colspan="1" rowspan="1">spare for future use</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">8 bytes</td>
+              <td colspan="1" rowspan="1">long</td>
+              <td colspan="1" rowspan="1">spare for future use</td>
+            
+</tr>
+          
+</table>
+<div class="frame note">
+<div class="label">Note</div>
+<div class="content">Spare space is guaranteed to be writen with "0", so that future 
+            use of field should not either not use "0" as a valid data item or 
+            pick 0 as a valid default value so that on the fly upgrade can assume 
+            that 0 means field was never assigned. </div>
+</div>
+<a name="N1016B"></a><a name="records"></a>
+<h3 class="boxed"> Records </h3>
+<p>The records section contains zero or more records. Each record starts 
+            with a Record Header</p>
+<table class="ForrestTable" cellspacing="1" cellpadding="4"> 
+            
+<caption>Record Header</caption>
+            
+<tr> 
+              
+<th colspan="1" rowspan="1">Type</th>
+              <th colspan="1" rowspan="1">Description</th>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">1 byte</td>
+              <td colspan="1" rowspan="1"> 
+<p>Status bits for the record header</p>
+                
+<table class="ForrestTable" cellspacing="1" cellpadding="4"> 
+                  
+<tr> 
+                    
+<td colspan="1" rowspan="1">RECORD_INITIAL</td>
+                    <td colspan="1" rowspan="1">used when record header is first initialized</td>
+                  
+</tr>
+                  
+<tr> 
+                    
+<td colspan="1" rowspan="1">RECORD_DELETED</td>
+                    <td colspan="1" rowspan="1">used to indicate the record has been deleted</td>
+                  
+</tr>
+                  
+<tr> 
+                    
+<td colspan="1" rowspan="1">RECORD_OVERFLOW</td>
+                    <td colspan="1" rowspan="1">used to indicate the record has been overflowed, it will 
+                      point to the overflow page and ID</td>
+                  
+</tr>
+                  
+<tr> 
+                    
+<td colspan="1" rowspan="1">RECORD_HAS_FIRST_FIELD</td>
+                    <td colspan="1" rowspan="1">used to indicate that firstField is stored will be stored. 
+                      When RECORD_OVERFLOW and RECORD_HAS_FIRST_FIELD both are 
+                      set, part of record is on the page, the record header also 
+                      stores the overflow point to the next part of the record.</td>
+                  
+</tr>
+                  
+<tr> 
+                    
+<td colspan="1" rowspan="1">RECORD_VALID_MASK</td>
+                    <td colspan="1" rowspan="1">A mask of valid bits that can be set currently, such that 
+                      the following assert can be made: </td>
+                  
+</tr>
+                
+</table>
+</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">compressed int</td>
+              <td colspan="1" rowspan="1">record identifier</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">compressed long</td>
+              <td colspan="1" rowspan="1">overflow page only if RECORD_OVERFLOW is set</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">compressed int</td>
+              <td colspan="1" rowspan="1">overflow id only if RECORD_OVERFLOW is set</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">compressed int</td>
+              <td colspan="1" rowspan="1">first field only if RECORD_HAS_FIRST_FIELD is set - otherwise 
+                0</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">compressed int</td>
+              <td colspan="1" rowspan="1">number of fields in this portion - only if RECORD_OVERFLOW is 
+                false OR RECORD_HAS_FIRST_FIELD is true - otherwise 0</td>
+            
+</tr>
+          
+</table>
+<div class="frame note">
+<div class="label">Long Rows</div>
+<div class="content"> A row is long if all of it's columns can't fit on a single page. 
+            When storing a long row, the segment of the row which fits on the 
+            page is left there, and a pointer column is added at the end of the 
+            row. It points to another row in the same container on a different 
+            page. That row will contain the next set of columns and a continuation 
+            pointer if necessary. The overflow portion will be on an "overflow" 
+            page, and that page may have overflow portions of other rows on it 
+            (unlike overflow columns). </div>
+</div>
+<p>The Record Header is followed by one or more fields. Each field contains 
+            a Field Header and optional Field Data.</p>
+<table class="ForrestTable" cellspacing="1" cellpadding="4"> 
+            
+<caption>Stored Field Header Format</caption>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">status</td>
+              <td colspan="1" rowspan="1"> 
+<p> The status is 1 byte, it indicates the state of the field. 
+                  A FieldHeader can be in the following states: </p>
+                  
+<table class="ForrestTable" cellspacing="1" cellpadding="4"> 
+                    
+<tr> 
+                      
+<td colspan="1" rowspan="1">NULL</td>
+                      <td colspan="1" rowspan="1">if the field is NULL, no field data length is stored</td>
+                    
+</tr>
+                    
+<tr> 
+                      
+<td colspan="1" rowspan="1">OVERFLOW</td>
+                      <td colspan="1" rowspan="1">indicates the field has been overflowed to another page. 
+                        overflow page and overflow ID is stored at the end of 
+                        the user data. field data length must be a number greater 
+                        or equal to 0, indicating the length of the field that 
+                        is stored on the current page. The format looks like this: 
+                        <img alt="" src="field-header-overflow.png">
+                        overflowPage will be written as compressed long, overflowId 
+                        will be written as compressed Int</td>
+                    
+</tr>
+                    
+<tr> 
+                      
+<td colspan="1" rowspan="1">NONEXISTENT</td>
+                      <td colspan="1" rowspan="1">the field no longer exists, e.g. column has been dropped 
+                        during an alter table</td>
+                    
+</tr>
+                    
+<tr> 
+                      
+<td colspan="1" rowspan="1">EXTENSIBLE</td>
+                      <td colspan="1" rowspan="1">the field is of user defined data type. The field may 
+                        be tagged.</td>
+                    
+</tr>
+                    
+<tr> 
+                      
+<td colspan="1" rowspan="1">TAGGED</td>
+                      <td colspan="1" rowspan="1">the field is TAGGED if and only if it is EXTENSIBLE.</td>
+                    
+</tr>
+                    
+<tr> 
+                      
+<td colspan="1" rowspan="1">FIXED</td>
+                      <td colspan="1" rowspan="1">the field is FIXED if and only if it is used in the 
+                        log records for version 1.2 and higher.</td>
+                    
+</tr>
+                  
+</table>
+                
+</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">fieldDataLength</td>
+              <td colspan="1" rowspan="1"> The fieldDataLength is only set if the field is not NULL. It 
+                is the length of the field that is stored on the current page. 
+                The fieldDataLength is a variable length CompressedInt. </td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">fieldData</td>
+              <td colspan="1" rowspan="1">
+<p> Overflow page and overflow id are stored as field data. If 
+                the overflow bit in status is set, the field data is the overflow 
+                information. When the overflow bit is not set in status, then, 
+                fieldData is the actually user data for the field. That means, 
+                field header consists only field status, and field data length. 
+                <br>
+                A non-overflow field: 
+                <br> 
+<img alt="" src="field-header-non-overflow.png"> <br>
+                An overflow field: 
+                <br> 
+<img alt="" src="field-header-overflow.png"> <br> 
+<strong>overflowPage 
+                  and overflowID</strong> 
+<br>
+                The overflowPage is a variable length CompressedLong, overflowID 
+                is a variable Length CompressedInt. They are only stored when 
+                the field state is OVERFLOW. And they are not stored in the field 
+                header. Instead, they are stored at the end of the field data. 
+                The reason we do that is to save a copy if the field has to overflow. </p>
+              
+</td>
+            
+</tr>
+          
+</table>
+<div class="frame note">
+<div class="label">Long Columns</div>
+<div class="content"> A column is long if it can't fit on a single page. A long column 
+            is marked as long in the base row, and it's field contains a pointer 
+            to a chain of other rows in the same container with contain the data 
+            of the row. Each of the subsequent rows is on a page to itself. Each 
+            subsquent row, except for the last piece has 2 columns, the first 
+            is the next segment of the row and the second is the pointer to the 
+            the following segment. The last segment only has the data segment. 
+          </div>
+</div>
+<a name="N102C5"></a><a name="slottable"></a>
+<h3 class="boxed">Slot Offset Table</h3>
+<p>The slot offset table is a table of 6 or 12 bytes per record, depending 
+          on the pageSize being less or greater than 64K: </p>
+<table class="ForrestTable" cellspacing="1" cellpadding="4"> 
+            
+<caption>Slot Table Record</caption>
+            
+<tr> 
+              
+<th colspan="1" rowspan="1">Size</th>
+              <th colspan="1" rowspan="1">Content</th>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">2 bytes (unsigned short) or 4 bytes (int)</td>
+              <td colspan="1" rowspan="1">page offset for the record that is assigned to the slot</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">2 bytes (unsigned short) or 4 bytes (int)</td>
+              <td colspan="1" rowspan="1">the length of the record on this page.</td>
+            
+</tr>
+            
+<tr> 
+              
+<td colspan="1" rowspan="1">2 bytes (unsigned short) or 4 bytes (int)</td>
+              <td colspan="1" rowspan="1">the length of the reserved number of bytes for this record on 
+                this page.</td>
+            
+</tr>
+          
+</table>
+<p>
+          First slot is slot 0. The slot table grows backwards. Slots are never 
+          left empty. </p>
+<a name="N1030C"></a><a name="checksum"></a>
+<h3 class="boxed">Checksum</h3>
+<p>8 bytes of a java.util.zip.CRC32 checksum of the entire's page contents 
+          without the 8 bytes representing the checksum.</p>
+</div>
+    
+<a name="N10317"></a><a name="allocpage"></a>
+<h2 class="boxed">Allocation Page</h2>
+<div class="section">
+<p> An allocation page of the file container extends a normal Stored page, 
+        with the exception that a hunk of space may be 'borrowed' by the file 
+        container to store the file header.</p>
+<p> The borrowed space is not visible to the alloc page even though it is 
+        present in the page data array. It is accessed directly by the FileContainer. 
+        Any change made to the borrowed space is not managed or seen by the allocation 
+        page.</p>
+<p> The reason for having this borrowed space is so that the container header 
+        does not need to have a page of its own. </p>
+<p> 
+        
+<strong>Page Format</strong>
+        
+<br>
+        An allocation page extends a stored page, the on disk format is different 
+        from a stored page in that N bytes are 'borrowed' by the container and 
+        the page header of an allocation page will be slightly bigger than a normal 
+        stored page. This N bytes are stored between the page header and the record 
+        space.</p>
+<p> The reason why this N bytes can't simply be a row is because it needs 
+        to be statically accessible by the container object to avoid a chicken 
+        and egg problem of the container object needing to instantiate an alloc 
+        page object before it can be objectified, and an alloc page object needing 
+        to instantiate a container object before it can be objectified. So this 
+        N bytes must be stored outside of the normal record interface yet it must 
+        be settable because only the first alloc page has this borrowed space. 
+        Other (non-first) alloc page have N == 0. 
+        <br>
+        
+<img alt="" src="alloc-page.png">
+      </p>
+</div>
+  
+</div>
+<!--+
+    |end content
+    +-->
+<div class="clearboth">&nbsp;</div>
+</div>
+<div id="footer">
+<!--+
+    |start bottomstrip
+    +-->
+<div class="lastmodified">
+<script type="text/javascript"><!--
+document.write("Last Published: " + document.lastModified);
+//  --></script>
+</div>
+<div class="copyright">
+ Copyright &copy; 2004-2005 Apache Software Foundation</div>
+<div id="feedback">
+    Send feedback about the website to:
+  <a id="feedbackto" href="mailto:derby-dev@db.apache.org?subject=Feedback%C2%A0papers/pageformats.html">derby-dev@db.apache.org</a>
+</div>
+<!--+
+    |end bottomstrip
+    +-->
+</div>
+</body>
+</html>

Modified: incubator/derby/site/trunk/src/documentation/content/xdocs/faq.xml
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/src/documentation/content/xdocs/faq.xml?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/src/documentation/content/xdocs/faq.xml (original)
+++ incubator/derby/site/trunk/src/documentation/content/xdocs/faq.xml Mon Jan 31 15:13:36 2005
@@ -110,7 +110,8 @@
 
     <faq id="createdb_OS_X">
       <question>
-        Why can't I create a new database on Mac OS X?
+        Why can't I create a new database or modify an existing database 
+	on Mac OS X?
       </question>
       <answer>
         <p>

Added: incubator/derby/site/trunk/src/documentation/content/xdocs/papers/alloc-page.aart
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/src/documentation/content/xdocs/papers/alloc-page.aart?view=auto&rev=149319
==============================================================================
--- incubator/derby/site/trunk/src/documentation/content/xdocs/papers/alloc-page.aart (added)
+++ incubator/derby/site/trunk/src/documentation/content/xdocs/papers/alloc-page.aart Mon Jan 31 15:13:36 2005
@@ -0,0 +1,5 @@
+                            borrowed   
+                         <------------->
++----------+-------------+---+---------+-------------------+-------------------+--------+
+| FormatId | pageHeader  | N | N-bytes | alloc-extend-rows | slot-offset-table |checksum|
++----------+-------------+---+---------+-------------------+-------------------+--------+

Added: incubator/derby/site/trunk/src/documentation/content/xdocs/papers/field-header-non-overflow.aart
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/src/documentation/content/xdocs/papers/field-header-non-overflow.aart?view=auto&rev=149319
==============================================================================
--- incubator/derby/site/trunk/src/documentation/content/xdocs/papers/field-header-non-overflow.aart (added)
+++ incubator/derby/site/trunk/src/documentation/content/xdocs/papers/field-header-non-overflow.aart Mon Jan 31 15:13:36 2005
@@ -0,0 +1,3 @@
++--------+-------------------+-------------+
+| status | <fieldDataLength> | <fieldData> |
++--------+-------------------+-------------+

Added: incubator/derby/site/trunk/src/documentation/content/xdocs/papers/field-header-overflow.aart
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/src/documentation/content/xdocs/papers/field-header-overflow.aart?view=auto&rev=149319
==============================================================================
--- incubator/derby/site/trunk/src/documentation/content/xdocs/papers/field-header-overflow.aart (added)
+++ incubator/derby/site/trunk/src/documentation/content/xdocs/papers/field-header-overflow.aart Mon Jan 31 15:13:36 2005
@@ -0,0 +1,3 @@
++--------+-------------------+----------------+--------------+
+| status | <fieldDataLength> | <overflowPage> | <overflowID> |
++--------+-------------------+----------------+--------------+

Modified: incubator/derby/site/trunk/src/documentation/content/xdocs/papers/index.xml
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/src/documentation/content/xdocs/papers/index.xml?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/src/documentation/content/xdocs/papers/index.xml (original)
+++ incubator/derby/site/trunk/src/documentation/content/xdocs/papers/index.xml Mon Jan 31 15:13:36 2005
@@ -18,6 +18,7 @@
 <ul>
 	<li> Architecture: <a href="derby_arch.html">Derby Engine Architecture
 	 Overview</a></li>
+        <li>Disk Page Format:<a href="pageformats.html">Derby On Disk Page Format</a></li>
         <li><a href="derby_htw.html">How Things Work</a> </li> 
 	<li>JDBC: <a href="JDBCImplementation.html">Derby JDBC Implementation
 		Notes</a></li>
@@ -173,6 +174,6 @@
 
 </section>
 
-<p><em>Last Updated: January 21, 2005</em></p>
+<p><em>Last Updated: January 31, 2005</em></p>
 </body>
 </document>

Added: incubator/derby/site/trunk/src/documentation/content/xdocs/papers/page-format.aart
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/src/documentation/content/xdocs/papers/page-format.aart?view=auto&rev=149319
==============================================================================
--- incubator/derby/site/trunk/src/documentation/content/xdocs/papers/page-format.aart (added)
+++ incubator/derby/site/trunk/src/documentation/content/xdocs/papers/page-format.aart Mon Jan 31 15:13:36 2005
@@ -0,0 +1,3 @@
++----------+-------------+-------------------+-------------------+----------+
+| formatId | page-header | records           | slot-offset-table | checksum |
++----------+-------------+-------------------+-------------------+----------+

Added: incubator/derby/site/trunk/src/documentation/content/xdocs/papers/pageformats.xml
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/src/documentation/content/xdocs/papers/pageformats.xml?view=auto&rev=149319
==============================================================================
--- incubator/derby/site/trunk/src/documentation/content/xdocs/papers/pageformats.xml (added)
+++ incubator/derby/site/trunk/src/documentation/content/xdocs/papers/pageformats.xml Mon Jan 31 15:13:36 2005
@@ -0,0 +1,372 @@
+<?xml version="1.0"?>
+<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V2.0//EN" "http://forrest.apache.org/dtd/document-v20.dtd">
+<document> 
+  <header> 
+    <title>Derby On Disk Page Format</title>
+    <abstract>This document describes the storage format of Derby disk pages. 
+    This is a work-in-progress derived from Javadoc comments and 
+    from explanations Mike Matrigali posted to the Derby lists. 
+    Please post questions, comments, and corrections to 
+    derby-dev@db.apache.org.
+    </abstract>
+  </header>
+  <body>
+
+
+    <section id="introduction"> 
+      <title> Introduction </title>
+      <p>Derby stores table and index data in Containers, which currently map 
+        to files in the 
+        <code>seg0</code>
+        directory of the database. Data is stored in pages within the container.</p>
+      <fixme author="Dibyendu Majumdar"> Do all containers map to a single file, or does each container map 
+        to a file? </fixme>
+      <p>A page contains a set of records, which can be accessed by "slot", which 
+        defines the order of the records on the page, or by "id" which defines 
+        the identity of the records on the page. Clients access records by both 
+        slot and id, depending on their needs.</p>
+      <p>There are two types of pages - Raw Stored Pages which hold data, and 
+        Raw Stored Alloc Pages which hold page allocation information.</p>
+      <p>A Table or a BTree index provides a row-based access mechanism (row-based 
+        access interface is known as conglomerate). Rows are mapped to records 
+        in pages, in case of a table, a single row can span multiple records in 
+        multiple pages.</p>
+    </section>
+    <section id="storedpage"> 
+      <title>Data Page Format</title>
+      <p>A data page is broken into five sections. 
+        <img src="page-format.png" alt=""/>
+      </p>
+      <section id="formatid"> 
+        <title>Format Id </title>
+        <p> The formatId is a 4 bytes array, it contains the format Id of this 
+          page. The possible values are RAW_STORE_STORED_PAGE or RAW_STORE_ALLOC_PAGE.</p>
+      </section>
+      <section id="pageheader"> 
+        <title> Page Header </title>
+        <p> The page header is a fixed size, 56 bytes. </p>
+          <table> 
+            <tr> 
+              <th>Size</th>
+              <th>Type</th>
+              <th>Description</th>
+            </tr>
+            <tr> 
+              <td>1 byte</td>
+              <td>boolean</td>
+              <td>is page an overflow page</td>
+            </tr>
+            <tr> 
+              <td>1 byte</td>
+              <td>byte</td>
+              <td><p>page status is either VALID_PAGE or INVALID_PAGE(a field 
+                  maintained in base page)</p>
+                <p>page goes thru the following transition: 
+                  <br/>
+                  VALID_PAGE &lt;-&gt; deallocated page -&gt; free page &lt;-&gt; 
+                  VALID_PAGE</p>
+                <p>deallocated and free page are both INVALID_PAGE as far as BasePage 
+                  is concerned. 
+                  <br/>
+                  When a page is deallocated, it transitioned from VALID_PAGE 
+                  to INVALID_PAGE. 
+                  <br/>
+                  When a page is allocated, it trnasitioned from INVALID_PAGE 
+                  to VALID_PAGE.</p></td>
+            </tr>
+            <tr> 
+              <td>8 bytes</td>
+              <td>long</td>
+              <td>pageVersion (a field maintained in base page)</td>
+            </tr>
+            <tr> 
+              <td>2 bytes</td>
+              <td>unsigned short</td>
+              <td>number of slots in slot offset table</td>
+            </tr>
+            <tr> 
+              <td>4 bytes</td>
+              <td>integer</td>
+              <td>next record identifier</td>
+            </tr>
+            <tr> 
+              <td>4 bytes</td>
+              <td>integer</td>
+              <td>generation number of this page (Future Use)</td>
+            </tr>
+            <tr> 
+              <td>4 bytes</td>
+              <td>integer</td>
+              <td>previous generation of this page (Future Use)</td>
+            </tr>
+            <tr> 
+              <td>8 bytes</td>
+              <td>bipLocation</td>
+              <td>the location of the beforeimage page (Future Use)</td>
+            </tr>
+            <tr> 
+              <td>2 bytes</td>
+              <td>unsigned short</td>
+              <td>number of deleted rows on page. (new release 2.0)</td>
+            </tr>
+            <tr> 
+              <td>2 bytes</td>
+              <td>unsigned short</td>
+              <td>% of the page to keep free for updates</td>
+            </tr>
+            <tr> 
+              <td>2 bytes</td>
+              <td>short</td>
+              <td>spare for future use</td>
+            </tr>
+            <tr> 
+              <td>4 bytes</td>
+              <td>long</td>
+              <td>spare for future use (encryption uses to write random bytes 
+                here).</td>
+            </tr>
+            <tr> 
+              <td>8 bytes</td>
+              <td>long</td>
+              <td>spare for future use</td>
+            </tr>
+            <tr> 
+              <td>8 bytes</td>
+              <td>long</td>
+              <td>spare for future use</td>
+            </tr>
+          </table>
+          <note>Spare space is guaranteed to be writen with "0", so that future 
+            use of field should not either not use "0" as a valid data item or 
+            pick 0 as a valid default value so that on the fly upgrade can assume 
+            that 0 means field was never assigned. </note>
+        
+      </section>
+      <section id="records"> 
+        <title> Records </title>
+        
+          <p>The records section contains zero or more records. Each record starts 
+            with a Record Header</p>
+          <table> 
+            <caption>Record Header</caption>
+            <tr> 
+              <th>Type</th>
+              <th>Description</th>
+            </tr>
+            <tr> 
+              <td>1 byte</td>
+              <td> <p>Status bits for the record header</p>
+                <table> 
+                  <tr> 
+                    <td>RECORD_INITIAL</td>
+                    <td>used when record header is first initialized</td>
+                  </tr>
+                  <tr> 
+                    <td>RECORD_DELETED</td>
+                    <td>used to indicate the record has been deleted</td>
+                  </tr>
+                  <tr> 
+                    <td>RECORD_OVERFLOW</td>
+                    <td>used to indicate the record has been overflowed, it will 
+                      point to the overflow page and ID</td>
+                  </tr>
+                  <tr> 
+                    <td>RECORD_HAS_FIRST_FIELD</td>
+                    <td>used to indicate that firstField is stored will be stored. 
+                      When RECORD_OVERFLOW and RECORD_HAS_FIRST_FIELD both are 
+                      set, part of record is on the page, the record header also 
+                      stores the overflow point to the next part of the record.</td>
+                  </tr>
+                  <tr> 
+                    <td>RECORD_VALID_MASK</td>
+                    <td>A mask of valid bits that can be set currently, such that 
+                      the following assert can be made: </td>
+                  </tr>
+                </table></td>
+            </tr>
+            <tr> 
+              <td>compressed int</td>
+              <td>record identifier</td>
+            </tr>
+            <tr> 
+              <td>compressed long</td>
+              <td>overflow page only if RECORD_OVERFLOW is set</td>
+            </tr>
+            <tr> 
+              <td>compressed int</td>
+              <td>overflow id only if RECORD_OVERFLOW is set</td>
+            </tr>
+            <tr> 
+              <td>compressed int</td>
+              <td>first field only if RECORD_HAS_FIRST_FIELD is set - otherwise 
+                0</td>
+            </tr>
+            <tr> 
+              <td>compressed int</td>
+              <td>number of fields in this portion - only if RECORD_OVERFLOW is 
+                false OR RECORD_HAS_FIRST_FIELD is true - otherwise 0</td>
+            </tr>
+          </table>
+          <note label="Long Rows"> A row is long if all of it's columns can't fit on a single page. 
+            When storing a long row, the segment of the row which fits on the 
+            page is left there, and a pointer column is added at the end of the 
+            row. It points to another row in the same container on a different 
+            page. That row will contain the next set of columns and a continuation 
+            pointer if necessary. The overflow portion will be on an "overflow" 
+            page, and that page may have overflow portions of other rows on it 
+            (unlike overflow columns). </note>
+          <p>The Record Header is followed by one or more fields. Each field contains 
+            a Field Header and optional Field Data.</p>
+          <table> 
+            <caption>Stored Field Header Format</caption>
+            <tr> 
+              <td>status</td>
+              <td> <p> The status is 1 byte, it indicates the state of the field. 
+                  A FieldHeader can be in the following states: </p>
+                  <table> 
+                    <tr> 
+                      <td>NULL</td>
+                      <td>if the field is NULL, no field data length is stored</td>
+                    </tr>
+                    <tr> 
+                      <td>OVERFLOW</td>
+                      <td>indicates the field has been overflowed to another page. 
+                        overflow page and overflow ID is stored at the end of 
+                        the user data. field data length must be a number greater 
+                        or equal to 0, indicating the length of the field that 
+                        is stored on the current page. The format looks like this: 
+                        <img src="field-header-overflow.png" alt=""/>
+                        overflowPage will be written as compressed long, overflowId 
+                        will be written as compressed Int</td>
+                    </tr>
+                    <tr> 
+                      <td>NONEXISTENT</td>
+                      <td>the field no longer exists, e.g. column has been dropped 
+                        during an alter table</td>
+                    </tr>
+                    <tr> 
+                      <td>EXTENSIBLE</td>
+                      <td>the field is of user defined data type. The field may 
+                        be tagged.</td>
+                    </tr>
+                    <tr> 
+                      <td>TAGGED</td>
+                      <td>the field is TAGGED if and only if it is EXTENSIBLE.</td>
+                    </tr>
+                    <tr> 
+                      <td>FIXED</td>
+                      <td>the field is FIXED if and only if it is used in the 
+                        log records for version 1.2 and higher.</td>
+                    </tr>
+                  </table>
+                </td>
+            </tr>
+            <tr> 
+              <td>fieldDataLength</td>
+              <td> The fieldDataLength is only set if the field is not NULL. It 
+                is the length of the field that is stored on the current page. 
+                The fieldDataLength is a variable length CompressedInt. </td>
+            </tr>
+            <tr> 
+              <td>fieldData</td>
+              <td><p> Overflow page and overflow id are stored as field data. If 
+                the overflow bit in status is set, the field data is the overflow 
+                information. When the overflow bit is not set in status, then, 
+                fieldData is the actually user data for the field. That means, 
+                field header consists only field status, and field data length. 
+                <br/>
+                A non-overflow field: 
+                <br/> <img src="field-header-non-overflow.png" alt=""/> <br/>
+                An overflow field: 
+                <br/> <img src="field-header-overflow.png" alt=""/> <br/> <strong>overflowPage 
+                  and overflowID</strong> <br/>
+                The overflowPage is a variable length CompressedLong, overflowID 
+                is a variable Length CompressedInt. They are only stored when 
+                the field state is OVERFLOW. And they are not stored in the field 
+                header. Instead, they are stored at the end of the field data. 
+                The reason we do that is to save a copy if the field has to overflow. </p>
+              </td>
+            </tr>
+          </table>
+          <note label="Long Columns"> A column is long if it can't fit on a single page. A long column 
+            is marked as long in the base row, and it's field contains a pointer 
+            to a chain of other rows in the same container with contain the data 
+            of the row. Each of the subsequent rows is on a page to itself. Each 
+            subsquent row, except for the last piece has 2 columns, the first 
+            is the next segment of the row and the second is the pointer to the 
+            the following segment. The last segment only has the data segment. 
+          </note>
+        
+      </section>
+      <section id="slottable"> 
+        <title>Slot Offset Table</title>
+        <p>The slot offset table is a table of 6 or 12 bytes per record, depending 
+          on the pageSize being less or greater than 64K: </p>
+          <table> 
+            <caption>Slot Table Record</caption>
+            <tr> 
+              <th>Size</th>
+              <th>Content</th>
+            </tr>
+            <tr> 
+              <td>2 bytes (unsigned short) or 4 bytes (int)</td>
+              <td>page offset for the record that is assigned to the slot</td>
+            </tr>
+            <tr> 
+              <td>2 bytes (unsigned short) or 4 bytes (int)</td>
+              <td>the length of the record on this page.</td>
+            </tr>
+            <tr> 
+              <td>2 bytes (unsigned short) or 4 bytes (int)</td>
+              <td>the length of the reserved number of bytes for this record on 
+                this page.</td>
+            </tr>
+          </table>
+		  <p>
+          First slot is slot 0. The slot table grows backwards. Slots are never 
+          left empty. </p>
+      </section>
+      <section id="checksum"> 
+        <title>Checksum</title>
+        <p>8 bytes of a java.util.zip.CRC32 checksum of the entire's page contents 
+          without the 8 bytes representing the checksum.</p>
+      </section>
+	</section>
+    <section id="allocpage"> 
+      <title>Allocation Page</title>
+      <p> An allocation page of the file container extends a normal Stored page, 
+        with the exception that a hunk of space may be 'borrowed' by the file 
+        container to store the file header.</p>
+      <p> The borrowed space is not visible to the alloc page even though it is 
+        present in the page data array. It is accessed directly by the FileContainer. 
+        Any change made to the borrowed space is not managed or seen by the allocation 
+        page.</p>
+      <p> The reason for having this borrowed space is so that the container header 
+        does not need to have a page of its own. </p>
+      <p> 
+        <strong>Page Format</strong>
+        <br/>
+        An allocation page extends a stored page, the on disk format is different 
+        from a stored page in that N bytes are 'borrowed' by the container and 
+        the page header of an allocation page will be slightly bigger than a normal 
+        stored page. This N bytes are stored between the page header and the record 
+        space.</p>
+      <p> The reason why this N bytes can't simply be a row is because it needs 
+        to be statically accessible by the container object to avoid a chicken 
+        and egg problem of the container object needing to instantiate an alloc 
+        page object before it can be objectified, and an alloc page object needing 
+        to instantiate a container object before it can be objectified. So this 
+        N bytes must be stored outside of the normal record interface yet it must 
+        be settable because only the first alloc page has this borrowed space. 
+        Other (non-first) alloc page have N == 0. 
+        <br/>
+        <img src="alloc-page.png" alt=""/>
+      </p>
+    </section>
+  </body>
+  <footer> 
+    <legal>This is a legal notice, so it is 
+      <strong>important</strong>
+      .</legal>
+  </footer>
+</document>

Modified: incubator/derby/site/trunk/src/documentation/content/xdocs/site.xml
URL: http://svn.apache.org/viewcvs/incubator/derby/site/trunk/src/documentation/content/xdocs/site.xml?view=diff&r1=149318&r2=149319
==============================================================================
--- incubator/derby/site/trunk/src/documentation/content/xdocs/site.xml (original)
+++ incubator/derby/site/trunk/src/documentation/content/xdocs/site.xml Mon Jan 31 15:13:36 2005
@@ -26,6 +26,7 @@
 
   <engine label="Derby Engine" href="papers/" tab="papers">
       <index label="Architecture"  href="derby_arch.html"/>
+      <pformat label="Disk Page Format" href="pageformats.html"/>
       <misc  label="How Things Work" href="derby_htw.html"/>
       <jdbc  label="JDBC"  href="JDBCImplementation.html"/>
   </engine>



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