0 Replies Latest reply on Oct 25, 2005 7:39 AM by jivkoto

    on-find read-ahead does not work

    jivkoto Newbie

      Hi,
      It seems that on-find read-ahead do not work properly. I?ve seen so many posts in this forum for this problem, and no concrete answer. So until then here is my problem too :)
      I have entity with 3 fields (2 of them is primary key). I am trying to use on-find read-ahead. And I expect that everything will be loaded when I call my findAll method. But instead of this there is one Select statement for everything. And N queries that loads the other field from the DB for every primary key. Which acts as on-load. Here is the log from the jboss console:
      10:17:39,046 DEBUG [EAttachmentToProcess#findAll] Executing SQL: SELECT t0_a.cAt
      tachId, t0_a.cProcessId, t0_a.cActId FROM tBPAttachProc t0_a

      10:17:39,250 DEBUG [EAttachmentToProcess] Executing SQL: SELECT cActId FROM tBPA
      ttachProc WHERE (cAttachId=? AND cProcessId=?)
      10:17:39,265 DEBUG [EAttachmentToProcess] Executing SQL: SELECT cActId FROM tBPA
      ttachProc WHERE (cAttachId=? AND cProcessId=?)
      ?? N TIMES

      As you see it is in the same transaction @ejb.transaction type="Required" (as noted in the Forum). Other thing is that I try and load-group for the activityId which is not in the PK for this table, and guess ? nothing changed. N+1 queries each time. It is killing me?
      Additional info: This is JBoss 3.2.6 on Windows XP

      Here comes my xDocleted entity.

      package com.some.attachment;

      import javax.ejb.CreateException;
      import javax.ejb.EntityBean;
      import javax.ejb.EntityContext;
      import javax.ejb.RemoveException;

      /**
      * Entity representing the relation many-to-many between attachments and process instances
      *
      * Standard entity bean, provides two finder methods (besides findByPK)- by attachment id
      * and by process id.
      *
      * @author nts
      * @version $Revision: 1.5 $
      *
      * @ejb.bean name = "EAttachmentToProcess"
      * type="CMP"
      * local-jndi-name="ejb/EAttachmentToProcessLocal"
      * jndi-name="ejb/EAttachmentToProcess"
      * prim-key-class="com.some.attachment.EAttachmentToProcessPK"
      * view-type="both"
      * cmp-version="2.x"
      *
      * @ejb.finder signature = "java.util.Collection findByAttachemntId(java.lang.String attachmentId)"
      * query = "SELECT Object(a) FROM EAttachmentToProcess a WHERE a.attachmentId = ?1"
      *
      * @ejb.finder signature = "java.util.Collection findByProcessId(java.lang.String processId)"
      * query = "SELECT Object(a) FROM EAttachmentToProcess a WHERE a.processId = ?1"
      *
      * @ejb.finder signature = "java.util.Collection findAll()"
      * query = "SELECT Object(a) FROM EAttachmentToProcess a"
      *
      * @jboss.query signature ="java.util.Collection findAll()"
      * query = "SELECT Object(a) FROM EAttachmentToProcess a"
      * strategy = "on-find"
      *
      * @ejb.transaction
      * type="Required"
      *
      * @ejb.permission role-name="admin"
      *
      * @ejb.persistence table-name = "tBPAttachProc"
      *
      * JBoss specific
      *
      * @jboss.persistence table-name = "tBPAttachProc" create-table = "false"
      *
      * @jboss.container-configuration name="EntityBean_Commit_A"
      * @jboss.read-ahead strategy="on-find"
      *
      * @jboss.entity-command name = "no-select-before-insert"
      *
      */
      public abstract class EAttachmentToProcessEJB
      implements EntityBean
      {

      private static final long serialVersionUID = 20050119L;

      private transient EntityContext context;

      /**
      * Part of the PK and also a FK to tAttachment
      *
      * @return
      *
      * @ejb.interface-method view-type = "both"
      * @ejb.persistence column-name = "cAttachId"
      * jdbc-type="CHAR"
      * sql-type="CHAR(36)"
      *
      */
      public abstract String getAttachmentId();


      /**
      *
      * @param id
      *
      * @ejb.interface-method view-type = "both"
      * @ejb.persistence column-name = "cAttachId"
      * jdbc-type="CHAR"
      * sql-type="CHAR(36)"
      *
      */
      public abstract void setAttachmentId(String id);


      /**
      * Part of the PK and also a FK to tProcInstance
      *
      * @return
      *
      * @ejb.interface-method view-type = "both"
      * @ejb.persistence column-name = "cProcessId"
      * jdbc-type="CHAR"
      * sql-type="CHAR(36)"
      *
      */
      public abstract String getProcessId();


      /**
      *
      * @param id
      *
      * @ejb.interface-method view-type = "both"
      * @ejb.persistence column-name = "cProcessId"
      * jdbc-type="CHAR"
      * sql-type="CHAR(36)"
      */
      public abstract void setProcessId(String id);


      /**
      * Additional info - id of the activity (receive, invoke ...)
      * @return
      *
      * @ejb.interface-method view-type = "both"
      * @ejb.persistence column-name = "cActId"
      * jdbc-type= "VARCHAR"
      * sql-type= "VARCHAR(512)"
      *
      */
      public abstract String getActivityId();


      /**
      * @ejb.interface-method view-type = "both"
      * @ejb.persistence column-name = "cActId"
      * jdbc-type= "VARCHAR"
      * sql-type= "VARCHAR(512)"
      */
      public abstract void setActivityId(String id);

      /**
      * @ejb.create-method view-type = "both"
      */
      public EAttachmentToProcessPK ejbCreate(String attId, String procId, String actId)
      throws CreateException
      {
      setAttachmentId(attId);
      setProcessId(procId);
      setActivityId(actId);
      EAttachmentToProcessPK pk = new EAttachmentToProcessPK(attId, procId);

      return pk;
      }

      ????. and so on

      }

      Here is snipet of my jbosscmp-jdbc.xml generated file


      <ejb-name>EAttachmentToProcess</ejb-name>
      <create-table>false</create-table>

      <read-ahead>
      on-find
      </read-ahead>
      <table-name>tBPAttachProc</table-name>

      <cmp-field>
      <field-name>attachmentId</field-name>
      <column-name>cAttachId</column-name>

      <jdbc-type>CHAR</jdbc-type>
      <sql-type>CHAR(36)</sql-type>

      </cmp-field>
      <cmp-field>
      <field-name>processId</field-name>
      <column-name>cProcessId</column-name>

      <jdbc-type>CHAR</jdbc-type>
      <sql-type>CHAR(36)</sql-type>

      </cmp-field>
      <cmp-field>
      <field-name>activityId</field-name>
      <column-name>cActId</column-name>

      <jdbc-type>VARCHAR</jdbc-type>
      <sql-type>VARCHAR(512)</sql-type>

      </cmp-field>


      <query-method>
      <method-name>findAll</method-name>
      <method-params>
      </method-params>
      </query-method>
      <jboss-ql>[CDATA[SELECT Object(a) FROM EAttachmentToProcess a]]</jboss-ql>

      <read-ahead>
      on-find
      </read-ahead>


      <entity-command name="no-select-before-insert">
      </entity-command>

      So if you help it will be great. If you say that there is bug is ok too. I just want to know where is the problem is it my fault?
      Best regards, Zhivko