Default Fetch Group Flags

Using the following flags can improve performance.

Setting -DAllowManagedFieldsInDefaultFetchGroup=true allows CMP fields that by default cannot be placed into the default fetch group to be loaded along with all other fields that are fetched when the CMP state is loaded into memory. These could be multiple fields mapped to the same column in the database table, for example, an instance field and a CMR. By default this flag is set to false.

For additional information, see level in Sun Java System Application Server 9.1 Application Deployment Guide.

Setting -DAllowMediatedWriteInDefaultFetchGroup specifies how updated CMP fields are written back to the database. If the flag is false, all fields in the CMP bean are written back to the database if at least one field in the default fetch group has been changed in a transaction. If the flag is true, only fields modified by the bean are written back to the database. Specifying true can improve performance, particularly on database tables with many columns that have not been updated. By default this flag is set to false.

To set one of these flags, use the asadmin create-jvm-options command. For example:

asadmin create-jvm-options --user adminuser -DAllowManagedFieldsInDefaultFetchGroup=true