Issue 459: Improve LOB documentation

h2/src/docsrc/help/help.csv

@@ -1268,9 +1268,13 @@ SET LOCK_TIMEOUT 1000
 "Commands (Other)","SET MAX_LENGTH_INPLACE_LOB","
 SET MAX_LENGTH_INPLACE_LOB int
 ","
-Sets the maximum size of an in-place LOB object. LOB objects larger that this
-size are stored in a separate file, otherwise stored directly in the database
-(in-place). The default max size is 1024.
+Sets the maximum size of an in-place LOB object. 
+
+If the 'h2.lobInDatabase' property is true, this is the maximum length of an LOB that is stored with the record itself,
+and the default value is 128.
+If the 'h2.lobInDatabase' property is false, this is the maximum length of an LOB that is stored in the database file,
+and the default value is 4096.
+
 This setting has no effect for in-memory databases.
 
 Admin rights are required to execute this command, as it affects all connections.

h2/src/docsrc/html/advanced.html

@@ -130,7 +130,7 @@ on the client side.
 
 <h3>When to use CLOB/BLOB</h3>
 <p>
-This database stores large LOB (CLOB and BLOB) objects as separate files.
+By default, this database stores large LOB (CLOB and BLOB) objects separate from the main table data.
 Small LOB objects are stored in-place, the threshold can be set using
 <a href="grammar.html#set_max_length_inplace_lob" class="notranslate" >MAX_LENGTH_INPLACE_LOB</a>,
 but there is still an overhead to use CLOB/BLOB. Because of this, BLOB and CLOB
@@ -138,6 +138,9 @@ should never be used for columns with a maximum size below about 200 bytes.
 The best threshold depends on the use case; reading in-place objects is faster
 than reading from separate files, but slows down the performance of operations
 that don't involve this column.
+<p>
+It is possible to configure the database to store LOB objects outside the database file,
+see the <a href="../javadoc/org/h2/constant/SysProperties.html#h2.lobInDatabase">h2.lobInDatase</a> property.
 </p>
 
 <h3>Large Object Compression</h3>

h2/src/docsrc/html/changelog.html

@@ -40,6 +40,7 @@ Change Log
 </li><li>Issue 274: Sybase/MSSQLServer compatibility - support index clause e.g. "select * from test (index table1_index)"
 </li><li>Fix bug in optimising SELECT * FROM A WHERE X=1 OR X=2 OR X=3 into SELECT * FROM A WHERE X IN (1,2,3)
 </li><li>Issue 442: groovy patch for SourceCompiler (function ALIAS)
+</li><li>Issue 459: Improve LOB documentation
 </li></ul>
 
 <h2>Version 1.3.171 (2013-03-17)</h2>

h2/src/main/org/h2/engine/Constants.java

@@ -197,13 +197,14 @@ public class Constants {
 
     /**
      * The default maximum length of an LOB that is stored in the database file.
+     * Only used if h2.lobInDatabase==false.
      */
     public static final int DEFAULT_MAX_LENGTH_INPLACE_LOB = 4096;
 
     /**
      * The default maximum length of an LOB that is stored with the record itself,
      * and not in a separate place.
-     * Only used if h2.lobInDatabase is enabled.
+     * Only used if h2.lobInDatabase==true.
      */
     public static final int DEFAULT_MAX_LENGTH_INPLACE_LOB2 = 128;