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Subject svn commit: r1078777 - in /openjpa/trunk/openjpa-project/src/doc/manual: jpa_overview_mapping.xml ref_guide_dbsetup.xml ref_guide_optimization.xml ref_guide_runtime.xml
Date Mon, 07 Mar 2011 14:02:33 GMT
Author: mtylenda
Date: Mon Mar  7 14:02:33 2011
New Revision: 1078777

OPENJPA-1376: Documentation update related to allocationSize property of @SequenceGenerator.


Modified: openjpa/trunk/openjpa-project/src/doc/manual/jpa_overview_mapping.xml
--- openjpa/trunk/openjpa-project/src/doc/manual/jpa_overview_mapping.xml (original)
+++ openjpa/trunk/openjpa-project/src/doc/manual/jpa_overview_mapping.xml Mon Mar  7 14:02:33
@@ -967,10 +967,11 @@ default.
                             allocationSize property
-<literal>int allocationSize</literal>: Some databases can pre-allocate groups
-of sequence values. This allows the database to service sequence requests from
-cache, rather than physically incrementing the sequence with every request. This
-allocation size defaults to 50.
+<literal>int allocationSize</literal>: The number of values to allocate in
+memory for each trip to the database. Allocating values in memory allows the JPA
+runtime to avoid accessing the database for every sequence request.
+This number also specifies the amount that the sequence value is incremented
+each time the sequence is accessed. Defaults to 50.

Modified: openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_dbsetup.xml
--- openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_dbsetup.xml (original)
+++ openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_dbsetup.xml Mon Mar  7 14:02:33
@@ -1914,8 +1914,9 @@ create a generated name. The default val
 <literal>NextSequenceQuery</literal>: A SQL string for obtaining a native
 sequence value. May use a placeholder of <literal>{0}</literal> for the variable
-sequence name. Defaults to a database-appropriate value.  For example, 
-<literal>"SELECT {0}.NEXTVAL FROM DUAL"</literal> for Oracle.
+sequence name and <literal>{1}</literal> for sequence increment.
+Defaults to a database-appropriate value. For example, 
+<literal>"SELECT {0}.NEXTVAL FROM DUAL"</literal> for Oracle database.
                 <listitem id="DBDictionary.NullTypeName">

Modified: openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_optimization.xml
--- openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_optimization.xml (original)
+++ openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_optimization.xml Mon Mar  7 14:02:33
@@ -301,8 +301,7 @@ it can become a factor.
                     <entry colname="desc">
 For applications that perform large bulk inserts, the retrieval of sequence 
-numbers can be a bottleneck.  Increasing sequence increments and using 
-table-based rather than native database sequences can reduce or eliminate 
+numbers can be a bottleneck. Increasing sequence allocation sizes can reduce or eliminate

 this bottleneck. In some cases, implementing your own sequence factory can 
 further optimize sequence number retrieval.

Modified: openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_runtime.xml
--- openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_runtime.xml (original)
+++ openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_runtime.xml Mon Mar  7 14:02:33
@@ -1661,8 +1661,11 @@ properties:
-<literal>Allocate</literal>: Some database can allocate values in-memory to
-service subsequent sequence requests faster.
+<literal>Allocate</literal>: The number of values to allocate on each database
+trip. Defaults to 50, meaning the class will set aside the next 50 numbers each
+time it accesses the sequence, which in turn means it only has to make a
+database trip to get new sequence numbers once every 50 sequence number

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