Changeset 5027

Timestamp:

Jul 28, 2009, 11:29:51 AM (14 years ago)

Author:

Nicklas Nordborg

Message:

Fixes #1350: Update to Hibernate 3.3.2

Updated documentation.

Location:

trunk/doc/src/docbook

Files:

• appendix/incompatible.xml (modified) (1 diff)
• developerdoc/core_ref.xml (modified) (3 diffs)

trunk/doc/src/docbook/appendix/incompatible.xml

@@ -43 +43 @@
     </para>
   </note>
+  
+  <sect1 id="appendix.incompatible.2.13">
+    <title>BASE 2.13 release</title>
+
+    <bridgehead>
+      Reporters, Raw data, Features and Array design blocks are now proxied
+    </bridgehead>
+    
+    <para>
+      This was previously not possible due to a Hibernate problem with
+      stateless sessions. See <ulink 
+      url="http://opensource.atlassian.com/projects/hibernate/browse/HHH-3528"
+      >http://opensource.atlassian.com/projects/hibernate/browse/HHH-3528</ulink>
+      for more information about this problem.
+    </para>
+    
+    <para>
+      This change means that items linking to reporter, raw data, feature or array design
+      blocks will no longer load the linked items automatically. This is usually 
+      not a problem since the proxies will be initialised if needed. The exception
+      is when a stateless session was used to create the proxy since the stateless
+      can't initialise proxies. In BASE, stateless sessions are only used by <classname
+      docapi="net.sf.based.core">DataQuery</classname> instances, eg. queries that
+      returns reporter, raw data or features. When this type of query is used and
+      when linked items are used in a way that causes proxy initialization the linked 
+      item must be explicitely FETCH JOIN-ed by the query. Here is an example:
+    </para>
+    
+    <programlisting language="java"><![CDATA[ 
+RawBioAssay rba = ...
+DataQuery<RawData> rawQuery = rba.getRawData();
+rawQuery.join(
+  Hql.leftJoin(null, "reporter", Item.REPORTER.getAlias(), null, true));
+// NOTE! Last parameter is 'true' to FETCH JOIN the reporter!!
+...
+DbControl dc = ...
+DataResultIterator<RawData> rawData = rawQuery.iterate(dc);
+while (rawData.hasNext())
+{
+  RawData rd = rawData.next();
+  ReporterData reporter = rd.getReporter();
+  int reporterId = reporter.getId();
+  // Always safe since getId() doesn't cause proxy initialization
+
+  reporter.getName();
+  // The above statement will fail in BASE 2.13 if 
+  // the FETCH JOIN is no included
+  ....
+}]]>
+</programlisting>
+  
+    <para>
+      The error message to look out for is:
+      <code> 
+      org.hibernate.SessionException: proxies cannot be fetched by a stateless session
+      </code>
+    </para>
+
+  </sect1>
   
   <sect1 id="appendix.incompatible.2.12">

trunk/doc/src/docbook/developerdoc/core_ref.xml

@@ -715 +715 @@
             is required that proxies are enabled for all items that are linked from any of 
             the batchable items, ie. <classname docapi="net.sf.basedb.core">RawBioAssay</classname>, 
-            <classname docapi="net.sf.basedb.core">ReporterType</classname>, <classname docapi="net.sf.basedb.core">ArrayDesignBlock</classname>, etc.
+            <classname docapi="net.sf.basedb.core">ReporterType</classname>, 
+            <classname docapi="net.sf.basedb.core">ArrayDesignBlock</classname>, etc.
+            If we don't do this Hibernate will generate multiple additional select
+            statements for the same parent item which will affect performance 
+            in a bad way.
           </para>
           
@@ -721 +725 @@
             On the other hand, the proxies created from a stateless session cannot later 
             be initialised. We have to get the ID from the proxy and the load the object 
-            using the regular session. This also means that a batchable class shouldn't 
-            use proxies.
+            using the regular session. But this can also results in lots of additional select
+            statements so if it is known before that we need some information it is recommended
+            that a FETCH JOIN is used so that we get fully initialized objects instead of
+            proxies to begin with.
           </para>
         </warning>
@@ -797 +803 @@
         <para>
           * = Do not use this setting for classes which are many-to-one linked from a batchable 
-          class. Always use this setting for batchable classes. See warning above!
+          class.
         </para>