Question

I have a problem with a page loading of data. rich:datatable is used to display list of announcements.

Announcement class include Set of AnnouncedLot class and in a mapping it is specified as

<set cascade="all,delete-orphan" lazy="false" name="lots" table="ad_lot">
<key column="lotId"/>
<many-to-many class="AnnouncedLot" column="anlotId"/>
</set>

AnnouncedLot class mapping is

<class name="AnnouncedLot" table="announcedLot">
  <id name="id" type="java.lang.Long" unsaved-value="-1">
     <generator class="native"/>
  </id>
  <property name="idValue" not-null="false" unique="true"/>
  <property name="databaseId" not-null="false" unique="true"/>
  <property length="4047" name="title"/>
  <property length="4047" name="description"/>
  <property length="4047" name="source"/>
  <property length="65534" name="adText"/>
  <property name="sum"/>
</class>

At the moment there are about 1,5 million of announcement in the database and 3,5 millions of lots. One announcement can have 1 or even 100 lots.

Page loads only 30 first results of an announcement query. It loads quickly when there are no lots in the database, but with lots it can take around 1,5 min.

I have tried to change lazy to true and to google this problem but haven’t found much. Can anyone help with this?

Update:

After checking what query takes a lot of time, I’ve found out that the rows counting query is the cause. Query contained lots.sum condition due to default filter parameter. I have change the filter so it doesn’t have to use the set and the performance has improved.

Thanks everyone for help.

Answer 1

Try to use batch-size attribute on the many-to-many association.

http://docs.jboss.org/hibernate/orm/3.3/reference/en/html/performance.html#performance-fetching-batch