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<section id="JCR.Statistics">
  <title>eXo JCR statistics</title>
  <para>This section will show you how to get and manage all statistics provided by eXo JCR.</para>
  
  <section id="JCR.Statistics.Database_access_layer">
    <title>Statistics on the Database Access Layer</title>

    <para>In order to have a better idea of the time spent into the database
    access layer, it can be interesting to get some statistics on that part of
    the code, knowing that most of the time spent into eXo JCR is mainly the
    database access. This statistics will then allow you to identify without
    using any profiler what is normally slow in this layer, which could help
    to fix the problem quickly.</para>

    <para>In case you use
    <envar>org.exoplatform.services.jcr.impl.storage.jdbc.optimisation.CQJDBCWorkspaceDataContainer</envar>
    or
    <envar>org.exoplatform.services.jcr.impl.storage.jdbc.JDBCWorkspaceDataContainer</envar>
    as <envar>WorkspaceDataContainer</envar>, you can get statistics on the
    time spent into the database access layer. The database access layer (in
    eXo JCR) is represented by the methods of the interface
    <envar>org.exoplatform.services.jcr.storage.WorkspaceStorageConnection</envar>,
    so for all the methods defined in this interface, we can have the
    following figures:</para>

    <itemizedlist>
      <listitem>
        <para>The minimum time spent into the method.</para>
      </listitem>

      <listitem>
        <para>The maximum time spent into the method.</para>
      </listitem>

      <listitem>
        <para>The average time spent into the method.</para>
      </listitem>

      <listitem>
        <para>The total amount of time spent into the method.</para>
      </listitem>

      <listitem>
        <para>The total amount of time the method has been called.</para>
      </listitem>
    </itemizedlist>

    <para>Those figures are also available globally for all the methods which
    gives us the global behavior of this layer.</para>

    <para>If you want to enable the statistics, you just need to set the JVM
    parameter called
    <emphasis>JDBCWorkspaceDataContainer.statistics.enabled</emphasis> to
    <emphasis>true</emphasis>. The corresponding CSV file is
    <emphasis>StatisticsJDBCStorageConnection-${creation-timestamp}.csv</emphasis>
    for more details about how the csv files are managed, please refer to the
    section dedicated to the statistics manager.</para>

    <para>The format of each column header is ${method-alias}-${metric-alias}.
    The metric alias are described in the statistics manager section.</para>

    <para>The name of the category of statistics corresponding to these
    statistics is <emphasis>JDBCStorageConnection</emphasis>, this name is
    mostly needed to access to the statistics through JMX.</para>

    <table>
      <title>Method Alias</title>

      <tgroup cols="2">
        <tbody>
          <row>
            <entry>global</entry>

            <entry>This is the alias for all the methods.</entry>
          </row>

          <row>
            <entry>getItemDataById</entry>

            <entry>This is the alias for the method
            <emphasis>getItemData(String identifier).</emphasis></entry>
          </row>

          <row>
            <entry>getItemDataByNodeDataNQPathEntry</entry>

            <entry>This is the alias for the method
            <emphasis>getItemData(NodeData parentData, QPathEntry
            name).</emphasis></entry>
          </row>

          <row>
            <entry>getChildNodesData</entry>

            <entry>This is the alias for the method
            <emphasis>getChildNodesData(NodeData parent).</emphasis></entry>
          </row>

          <row>
            <entry>getChildNodesCount</entry>

            <entry>This is the alias for the method
            <emphasis>getChildNodesCount(NodeData parent).</emphasis></entry>
          </row>

          <row>
            <entry>getChildPropertiesData</entry>

            <entry>This is the alias for the method
            <emphasis>getChildPropertiesData(NodeData
            parent).</emphasis></entry>
          </row>

          <row>
            <entry>listChildPropertiesData</entry>

            <entry>This is the alias for the method
            <emphasis>listChildPropertiesData(NodeData
            parent).</emphasis></entry>
          </row>

          <row>
            <entry>getReferencesData</entry>

            <entry>This is the alias for the method
            <emphasis>getReferencesData(String
            nodeIdentifier).</emphasis></entry>
          </row>

          <row>
            <entry>commit</entry>

            <entry>This is the alias for the method
            <emphasis>commit().</emphasis></entry>
          </row>

          <row>
            <entry>addNodeData</entry>

            <entry>This is the alias for the method <emphasis>add(NodeData
            data).</emphasis></entry>
          </row>

          <row>
            <entry>addPropertyData</entry>

            <entry>This is the alias for the method <emphasis>add(PropertyData
            data).</emphasis></entry>
          </row>

          <row>
            <entry>updateNodeData</entry>

            <entry>This is the alias for the method <emphasis>update(NodeData
            data).</emphasis></entry>
          </row>

          <row>
            <entry>updatePropertyData</entry>

            <entry>This is the alias for the method
            <emphasis>update(PropertyData data).</emphasis></entry>
          </row>

          <row>
            <entry>deleteNodeData</entry>

            <entry>This is the alias for the method <emphasis>delete(NodeData
            data).</emphasis></entry>
          </row>

          <row>
            <entry>deletePropertyData</entry>

            <entry>This is the alias for the method
            <emphasis>delete(PropertyData data).</emphasis></entry>
          </row>

          <row>
            <entry>renameNodeData</entry>

            <entry>This is the alias for the method <emphasis>rename(NodeData
            data).</emphasis></entry>
          </row>

          <row>
            <entry>rollback</entry>

            <entry>This is the alias for the method
            <emphasis>rollback().</emphasis></entry>
          </row>

          <row>
            <entry>isOpened</entry>

            <entry>This is the alias for the method
            <emphasis>isOpened().</emphasis></entry>
          </row>

          <row>
            <entry>close</entry>

            <entry>This is the alias for the method
            <emphasis>close().</emphasis></entry>
          </row>
        </tbody>
      </tgroup>
    </table>
  </section>

  <section id="JCR.Statistics.Statistics_On_JCR_API_Accesses">
    <title>Statistics on the JCR API accesses</title>

    <para>In order to know exactly how your application uses eXo JCR, it can
    be interesting to register all the JCR API accesses in order to easily
    create real life test scenario based on pure JCR calls and also to tune
    your eXo JCR to better fit your requirements.</para>

    <para>In order to allow you to specify the configuration which part of eXo
    JCR needs to be monitored without applying any changes in your code
    and/or building anything, we choose to rely on the Load-time Weaving
    proposed by AspectJ.</para>

    <para>To enable this feature, you will have to add in your classpath the
    following jar files:</para>

    <itemizedlist>
      <listitem>
        <para><emphasis>exo.jcr.component.statistics-X.Y.Z</emphasis>.jar
        corresponding to your eXo JCR version that you can get from the jboss
        maven repository <ulink
        url="https://repository.jboss.org/nexus/content/groups/public/org/exoplatform/jcr/exo.jcr.component.statistics">https://repository.jboss.org/nexus/content/groups/public/org/exoplatform/jcr/exo.jcr.component.statistics</ulink>.</para>
      </listitem>

      <listitem>
        <para>aspectjrt-1.6.8.jar that you can get from the main maven
        repository <ulink
        url="http://repo2.maven.org/maven2/org/aspectj/aspectjrt"><uri>http://repo2.maven.org/maven2/org/aspectj/aspectjrt</uri></ulink>.</para>
      </listitem>
    </itemizedlist>

    <para>You will also need to get aspectjweaver-1.6.8.jar from the main
    maven repository <ulink
    url="http://repo2.maven.org/maven2/org/aspectj/aspectjweaver">http://repo2.maven.org/maven2/org/aspectj/aspectjweaver</ulink>.
    At this stage, to enable the statistics on the JCR API accesses, you will
    need to add the JVM parameter
    <emphasis>-javaagent:${pathto}/aspectjweaver-1.6.8.jar</emphasis> to your
    command line, for more details please refer to <ulink
    url="http://www.eclipse.org/aspectj/doc/released/devguide/ltw-configuration.html">http://www.eclipse.org/aspectj/doc/released/devguide/ltw-configuration.html</ulink>.</para>

    <para>By default, the configuration will collect statistics on all the
    methods of the internal interfaces
    <emphasis>org.exoplatform.services.jcr.core.ExtendedSession</emphasis> and
    <emphasis>org.exoplatform.services.jcr.core.ExtendedNode</emphasis>, and
    the JCR API interface <emphasis>javax.jcr.Property</emphasis>. To add
    and/or remove some interfaces to monitor, you have two configuration files
    to change that are bundled into the jar
    <emphasis>exo.jcr.component.statistics-X.Y.Z</emphasis>.jar, which are
    <emphasis>conf/configuration.xml</emphasis> and
    <emphasis>META-INF/aop.xml</emphasis>.</para>

    <para>The file content below is the content of
    <emphasis>conf/configuration.xml</emphasis> that you will need to modify
    to add and/or remove the full qualified name of the interfaces to monitor,
    into the list of parameter values of the init param called
    <emphasis>targetInterfaces</emphasis>.</para>

    <programlisting language="xml">&lt;configuration xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.exoplatform.org/xml/ns/kernel_1_3.xsd http://www.exoplatform.org/xml/ns/kernel_1_3.xsd"
 xmlns="http://www.exoplatform.org/xml/ns/kernel_1_3.xsd"&gt;

 &lt;component&gt;
   &lt;type&gt;org.exoplatform.services.jcr.statistics.JCRAPIAspectConfig&lt;/type&gt;
   &lt;init-params&gt;
     &lt;values-param&gt;
       &lt;name&gt;targetInterfaces&lt;/name&gt;
       &lt;value&gt;org.exoplatform.services.jcr.core.ExtendedSession&lt;/value&gt;
       &lt;value&gt;org.exoplatform.services.jcr.core.ExtendedNode&lt;/value&gt;
       &lt;value&gt;javax.jcr.Property&lt;/value&gt;
     &lt;/values-param&gt;
   &lt;/init-params&gt;
  &lt;/component&gt;
&lt;/configuration&gt;</programlisting>

    <para>The file content below is the content of
    <emphasis>META-INF/aop.xml</emphasis> that you will need to modify to
    add and/or remove the full qualified name of the interfaces to monitor,
    into the expression filter of the pointcut called
    <emphasis>JCRAPIPointcut</emphasis>. As you can see below, by default only
    JCR API calls from the exoplatform packages are took into account, don't
    hesistate to modify this filter to add your own package names.</para>

    <programlisting language="xml">&lt;aspectj&gt;
  &lt;aspects&gt;
    &lt;concrete-aspect name="org.exoplatform.services.jcr.statistics.JCRAPIAspectImpl" extends="org.exoplatform.services.jcr.statistics.JCRAPIAspect"&gt;
      &lt;pointcut name="JCRAPIPointcut"
        expression="(target(org.exoplatform.services.jcr.core.ExtendedSession) || target(org.exoplatform.services.jcr.core.ExtendedNode) || target(javax.jcr.Property)) &amp;amp;&amp;amp; call(public * *(..))" /&gt;
    &lt;/concrete-aspect&gt;
  &lt;/aspects&gt;
  &lt;weaver options="-XnoInline"&gt;
    &lt;include within="org.exoplatform..*" /&gt;
  &lt;/weaver&gt;
&lt;/aspectj&gt; </programlisting>

    <para>The corresponding CSV files are of type
    <emphasis>Statistics${interface-name}-${creation-timestamp}.csv</emphasis>
    for more details about how the csv files are managed, please refer to the
    section dedicated to the statistics manager.</para>

    <para>The format of each column header is ${method-alias}-${metric-alias}.
    The method alias will be of type ${method-name}(list of parameter types
    separeted by ; to be compatible with the CSV format).</para>

    <para>The metric alias are described in the statistics manager
    section.</para>

    <para>The name of the category of statistics corresponding to these
    statistics is the simple name of the monitored interface (e.g.
    ExtendedSession for org.exoplatform.services.jcr.core.ExtendedSession),
    this name is mostly needed to access to the statistics through JMX.</para>

    <remark>Please note that this feature will affect the performances of eXo
    JCR so it must be used with caution.</remark>
  </section>

  <section id="JCR.Statistics.Statistics_Manager">
    <title>Statistics Manager</title>

    <para>The statistics manager manages all the statistics provided by eXo
    JCR, it is responsible of printing the data into the CSV files and also
    exposing the statistics through JMX and/or Rest.</para>

    <para>The statistics manager will create all the CSV files for each
    category of statistics that it manages, the format of those files is
    <emphasis>Statistics${category-name}-${creation-timestamp}.csv</emphasis>.
    Those files will be created into the user directory if it is possible
    otherwise it will create them into the temporary directory. The format of
    those files is <envar>CSV</envar> (i.e. Comma-Seperated Values), one new
    line will be added regularily (every 5 seconds by default) and one last
    line will be added at JVM exit. Each line, will be composed of the 5
    figures described below for each method and globaly for all the
    methods.</para>

    <para><table>
        <title>Metric Alias</title>

        <tgroup cols="2">
          <tbody>
            <row>
              <entry>Min</entry>

              <entry>The minimum time spent into the method expressed in
              milliseconds.</entry>
            </row>

            <row>
              <entry>Max</entry>

              <entry>The maximum time spent into the method expressed in
              milliseconds.</entry>
            </row>

            <row>
              <entry>Total</entry>

              <entry>The total amount of time spent into the method expressed
              in milliseconds.</entry>
            </row>

            <row>
              <entry>Avg</entry>

              <entry>The average time spent into the method expressed in
              milliseconds.</entry>
            </row>

            <row>
              <entry>Times</entry>

              <entry>The total amount of times the method has been
              called.</entry>
            </row>
          </tbody>
        </tgroup>
      </table>You can disable the persistence of the statistics by setting the
    JVM parameter called
    <emphasis>JCRStatisticsManager.persistence.enabled</emphasis> to
    <emphasis>false</emphasis>, by default, it is set to
    <emphasis>true</emphasis>. You can aslo define the period of time between
    each record (i.e. line of data into the file) by setting the JVM parameter
    called <emphasis>JCRStatisticsManager.persistence.timeout</emphasis> to
    your expected value expressed in milliseconds, by default it is set to
    <emphasis>5000</emphasis>.</para>

    <para>You can also access to the statistics thanks to JMX, the available
    methods are the following:</para>

    <para><table>
        <title>JMX Methods</title>

        <tgroup cols="2">
          <tbody>
            <row>
              <entry>getMin</entry>

              <entry>Give the minimum time spent into the method corresponding
              to the given category name and statistics name. The expected
              arguments are the name of the category of statistics (e.g.
              JDBCStorageConnection) and the name of the expected method or
              global for the global value.</entry>
            </row>

            <row>
              <entry>getMax</entry>

              <entry>Give the maximum time spent into the method corresponding
              to the given category name and statistics name. The expected
              arguments are the name of the category of statistics (e.g.
              JDBCStorageConnection) and the name of the expected method or
              global for the global value.</entry>
            </row>

            <row>
              <entry>getTotal</entry>

              <entry>Give the total amount of time spent into the method
              corresponding to the given category name and statistics name.
              The expected arguments are the name of the category of
              statistics (e.g. JDBCStorageConnection) and the name of the
              expected method or global for the global value.</entry>
            </row>

            <row>
              <entry>getAvg</entry>

              <entry>Give the average time spent into the method corresponding
              to the given category name and statistics name. The expected
              arguments are the name of the category of statistics (e.g.
              JDBCStorageConnection) and the name of the expected method or
              global for the global value.</entry>
            </row>

            <row>
              <entry>getTimes</entry>

              <entry>Give the total amount of times the method has been called
              corresponding to the given ,category name and statistics name.
              The expected arguments are the name of the category of
              statistics (e.g. JDBCStorageConnection) and the name of the
              expected method or global for the global value.</entry>
            </row>

            <row>
              <entry>reset</entry>

              <entry>Reset the statistics for the given category name and
              statistics name. The expected arguments are the name of the
              category of statistics (e.g. JDBCStorageConnection) and the name
              of the expected method or global for the global value.</entry>
            </row>

            <row>
              <entry>resetAll</entry>

              <entry>Reset all the statistics for the given category name. The
              expected argument is the name of the category of statistics
              (e.g. JDBCStorageConnection).</entry>
            </row>
          </tbody>
        </tgroup>
      </table>The full name of the related MBean is
    <emphasis>exo:service=statistic, view=jcr</emphasis>.</para>
  </section>
</section>
