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From Kevin Sutter <kwsut...@gmail.com>
Subject Re: svn commit: r741275 - in /openjpa/trunk: openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/conf/ openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/jdbc/sqlcache/ openjpa-project/src/doc/manual/
Date Thu, 05 Feb 2009 20:18:38 GMT
Hi Pinaki,
Was the QuerySQLCache always in the openjpa.jdbc.* configuration?  Or, did
it get moved from the openjpa.* package?  Maybe you are just correcting the
documentation (and code) to be consistent, but I can't tell without more
digging.  My concern is that we can't just move the location of a
configuration option without some migration issues.  Hopefully, this is just
a cleanup exercise.

Thanks,
Kevin

On Thu, Feb 5, 2009 at 2:06 PM, <ppoddar@apache.org> wrote:

> Author: ppoddar
> Date: Thu Feb  5 20:06:02 2009
> New Revision: 741275
>
> URL: http://svn.apache.org/viewvc?rev=741275&view=rev
> Log:
> OPENJPA-703: Update Prepared Query Cache documentation.
>
> Modified:
>
>  openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/conf/JDBCConfigurationImpl.java
>
>  openjpa/trunk/openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/jdbc/sqlcache/TestPreparedQueryCache.java
>    openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_caching.xml
>    openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_conf.xml
>
> Modified:
> openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/conf/JDBCConfigurationImpl.java
> URL:
> http://svn.apache.org/viewvc/openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/conf/JDBCConfigurationImpl.java?rev=741275&r1=741274&r2=741275&view=diff
>
> ==============================================================================
> ---
> openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/conf/JDBCConfigurationImpl.java
> (original)
> +++
> openjpa/trunk/openjpa-jdbc/src/main/java/org/apache/openjpa/jdbc/conf/JDBCConfigurationImpl.java
> Thu Feb  5 20:06:02 2009
> @@ -305,7 +305,7 @@
>         // This plug-in is declared in superclass but defined here
>         // because PreparedQueryCache is currently available for JDBC
>         // backend only
> -        preparedQueryCachePlugin = addPlugin("QuerySQLCache", true);
> +        preparedQueryCachePlugin = addPlugin("jdbc.QuerySQLCache", true);
>         aliases = new String[] {
>             "true",
> "org.apache.openjpa.jdbc.kernel.PreparedQueryCacheImpl",
>             "false", null
>
> Modified:
> openjpa/trunk/openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/jdbc/sqlcache/TestPreparedQueryCache.java
> URL:
> http://svn.apache.org/viewvc/openjpa/trunk/openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/jdbc/sqlcache/TestPreparedQueryCache.java?rev=741275&r1=741274&r2=741275&view=diff
>
> ==============================================================================
> ---
> openjpa/trunk/openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/jdbc/sqlcache/TestPreparedQueryCache.java
> (original)
> +++
> openjpa/trunk/openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/jdbc/sqlcache/TestPreparedQueryCache.java
> Thu Feb  5 20:06:02 2009
> @@ -73,7 +73,7 @@
>        public void setUp() throws Exception {
>                super.setUp(CLEAR_TABLES, Company.class, Department.class,
>                    Employee.class, Address.class,
> -                               "openjpa.QuerySQLCache",
> +                               "openjpa.jdbc.QuerySQLCache",
>                                "true(excludes='select count(p) from Company
> p;select count(p) from Department p')");
>                createTestData();
>        }
>
> Modified:
> openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_caching.xml
> URL:
> http://svn.apache.org/viewvc/openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_caching.xml?rev=741275&r1=741274&r2=741275&view=diff
>
> ==============================================================================
> --- openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_caching.xml
> (original)
> +++ openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_caching.xml Thu
> Feb  5 20:06:02 2009
> @@ -1022,48 +1022,83 @@
>                                </tbody>
>                        </tgroup>
>                </table>
> -       </section>
> +       </section>
> +
>     <section id="ref_guide_cache_querysql">
> -        <title>
> -            Query SQL Cache
> -        </title>
> +        <title>Prepared SQL Cache</title>
>         <indexterm zone="ref_guide_cache_querysql">
> -            <primary>
> -                caching
> -            </primary>
> -            <secondary>
> -                query sql cache
> -            </secondary>
> +            <primary>caching</primary>
> +            <secondary>query sql cache</secondary>
>         </indexterm>
> -<para>
> -The Query SQL Cache caches SQL statements corresponding to JPQL queries.
> +         <para>
> +Prepared SQL Cache caches SQL statements corresponding to JPQL queries.
>  If a JPQL query is executed more than once in the same or different
> persistence
> -context, the SQL statement generated during the first execution is cached
> and
> +contexts, the SQL statement generated during the first execution is cached
> and
>  executed directly for subsequent execution. Direct execution of SQL offers
>  significant performance gain as it saves the cost of parsing query string
> and,
>  more importantly, populating the query expression tree during every
> execution.
> +Relative performance gain becomes higher as the complexity of forming a
> SQL
> +query from a JPQL string increases. For example, a JPQL query
> <code>Q1</code>
> +that involves multiple joins across tables takes more computation to
> translate
> +into a SQL statement than a JPQL query <code>Q2</code> to select by simple
> +primary key identifier. Correspondingly, repeated execution of
> <code>Q1</code>
> +will gain more performance advantage than <code>Q2</code> with Prepared
> SQL
> +Cache.
>  </para>
>  <para>
> -The Query SQL Cache is configured by the <link
> linkend="openjpa.jdbc.QuerySQLCache">
> -<literal>openjpa.QuerySQLCache</literal></link> configuration property.
> This
> +Prepared SQL Cache is configured by the <link
> linkend="openjpa.jdbc.QuerySQLCache">
> +<literal>openjpa.jdbc.QuerySQLCache</literal></link> configuration
> property. This
>  property accepts a a plugin string (see <xref
> linkend="ref_guide_conf_plugins"/>)
> -with value of <literal>true</literal> or <literal>false</literal>.
> +with value of <literal>true</literal> or <literal>false</literal>.
The
> default
> +is <literal>true</literal>.
>  </para>
>  <para>
> -Depending upon the mapping of your persistent domain object model,
> -lazy/eager fetch settings on the relation paths and fetch configuration, a
> -single JPQL may result in multiple SQL statements. If a JPQL query
> requires
> -more than one SQL statement to be executed, then the JPQL query is not
> cached.
> -The other critical point to remember while using the Query SQL Cache is
> that
> -change in fetch plan or locking mode may cause a different target SQL
> statement
> -than the original. But Query SQL Cache does not track such changes and
> reuses
> -the cached SQL under the assumption that the query execution context has
> -remained unchanged.
> +Following salient points to be noted regarding usage of Prepared Query
> Cache.
> +<itemizedlist>
> +       <listitem>
> +       Prepared Query Cache uses the original JPQL string as the key to
> index the
> +       corresponding SQL statement. Hence the JPQL strings that are
> semantically
> +       identical but differ by character case or identification variables
> are
> +       considered as different by this cache.
> +       </listitem>
> +       <listitem>
> +    A JPQL query may not always translate into a
> <emphasis>single</emphasis>
> +    SQL query. The JPQL queries that require multiple select statements
> are
> +    never cached.
> +    </listitem>
> +       <listitem>
> +       Same JPQL query may result into different SQL statements under
> different
> +       execution context. Execution context parameters such as fetch
> configuration
> +       or locking mode determine the resultant SQL. However, Prepared SQL
> Cache
> +       <emphasis>does not</emphasis> capture the execution context
> parameters
> +       while caching a generated SQL.
> +       </listitem>
> +       <listitem>
> +       The named or positional parameters of a JPQL query can be set to
> different
> +       values across executions. In general, the corresponding cached SQL
> statement
> +       will be re-parameterized accordingly. However, the parameter value
> itself can
> +       determine the SQL query. For example, when a JPQL query compares a
> relation
> +       field for equality against a parameter <code>p</code>, whether the
> actual
> +       value of <code>p</code> is <code>null</code> or not will
determine
> the
> +       generated SQL statement. Another example is collection valued
> parameter for
> +       <code>IN</code> expression. Each element of a collection valued
> parameter
> +       results into a SQL parameter. If a collection valued parameter
> across
> +       executions are set to different number of elements, then the
> parameters of
> +       the cached SQL do not correspond. If such situations are
> encountered while
> +       re-parameterizing the cached SQL, the cached version is not reused
> and the
> +       original JPQL query is used to generate a new SQL statement for
> execution.
> +       </listitem>
> +       <listitem>
> +       JPQL query that returns a <emphasis>numeric</emphasis> value such
> as
> +       <code>SELECT count(p) FROM PObject p</code> is never cached.
> +       </listitem>
> +</itemizedlist>
>  </para>
>  <para>
> -Several mechanisms are available to the application to deactivate SQL
> cacheing
> -for a query.
> -       <listitem>A user application can deactivate SQL Query Cache
> +Several mechanisms are available to the application to bypass SQL caching
> +for a JPQL query.
> +<itemizedlist>
> +       <listitem>A user application can disable Prepared SQL Cache
>        for entire lifetime of a persistence context by invoking the
> following
>        method on OpenJPA's EntityMananger interface:
>        <programlisting>
> @@ -1071,11 +1106,11 @@
>        </programlisting>
>        </listitem>
>        <listitem>
> -       A user application can instruct a particular execution of a JPQL
> query to
> +       A user application can instruct particular execution of a JPQL
> query to
>        ignore any cached SQL query, by setting
>        <literal>QueryHints.HINT_IGNORE_PREPARED_QUERY</literal> or
>        <literal>"openjpa.hint.IgnorePreparedQuery"</literal> to
> <literal>true</literal>
> -       via standard <literal>javax.persistence.Query.setHints()</literal>.
> If a
> +       via standard <literal>javax.persistence.Query.setHint(String,
> Object)</literal> method. If a
>        SQL query has been cached corresponding to the JPQL query prior to
> this
>        execution, then the cached SQL remains in the cache and will be
> reused
>        for any subsequent execution of the same JPQL query.
> @@ -1085,10 +1120,19 @@
>        ignore any cached SQL query, by setting
>        <literal>QueryHints.HINT_INVALIDATE_PREPARED_QUERY</literal> or
>        <literal>"openjpa.hint.InvalidatePreparedQuery"</literal> to
> <literal>true</literal>
> -       The SQL query is removed from the cache and the JPQL query will
> never be
> -       cached again during the lifetime of the entire persistence unit
> i.e.
> -       EntityManagerFactory.
> +       The SQL query is removed from the cache. Also the JPQL query will
> never be
> +       cached again during the lifetime of the entire persistence unit.
> +       </listitem>
> +       <listitem>
> +       Plug-in property <literal>openjpa.jdbc.QuerySQLCache</literal> can
> be
> +       configured to exclude certain JPQL queries as shown below.
> +       <programlisting>
> +       &lt;property name="openjpa.jdbc.QuerySQLCache"
> value="true(excludes='select c from Company c;select d from Department
> d')"/&gt;
> +       </programlisting>
> +       will never cache JPQL queries <code>select c from Company c</code>
> and
> +       <code>select d from Department d</code>.
>        </listitem>
> +       </itemizedlist>
>  </para>
>
>     </section>
>
> Modified: openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_conf.xml
> URL:
> http://svn.apache.org/viewvc/openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_conf.xml?rev=741275&r1=741274&r2=741275&view=diff
>
> ==============================================================================
> --- openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_conf.xml
> (original)
> +++ openjpa/trunk/openjpa-project/src/doc/manual/ref_guide_conf.xml Thu Feb
>  5 20:06:02 2009
> @@ -3516,7 +3516,8 @@
>  <classname>org.apache.openjpa.meta.MetaDataFactory</classname></ulink>
to
> use to
>  store and retrieve object-relational mapping information for your
> persistent
>  classes. See <xref linkend="ref_guide_mapping_factory"/> for details.
> -            </para>
> +            </para>
> +
>         </section>
>         <section id="openjpa.jdbc.QuerySQLCache">
>             <title>
> @@ -3524,7 +3525,7 @@
>             </title>
>             <indexterm zone="openjpa.jdbc.QuerySQLCache">
>                 <primary>
> -                    QuerySQLCache
> +                    Prepared SQL Cache
>                 </primary>
>             </indexterm>
>             <indexterm zone="openjpa.jdbc.QuerySQLCache">
> @@ -3548,10 +3549,9 @@
>             </para>
>             <para>
>  <emphasis role="bold">Description:</emphasis> A plugin string (see
> -<xref linkend="ref_guide_conf_plugins"/>) describing the
> -<classname>java.util.Map</classname> to use for caching of the SQL string
> -used by the find operation.  See <xref
> linkend="ref_guide_cache_querysql"/> for
> -details.
> +<xref linkend="ref_guide_conf_plugins"/>) describing the options to cache
> and
> +reuse SQL statements generated for JPQL queries.
> +See <xref linkend="ref_guide_cache_querysql"/> for details.
>             </para>
>         </section>
>         <section id="openjpa.jdbc.ResultSetType">
>
>
>

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