Rules for Partial Replication Filtering

This section describes rules and best practices to follow when specifying naming contexts in partial replication. The discussion in this section relies on the sample naming context illustrated in Figure 24-13.

Figure 24-13 A Sample Naming Context

Text description of the illustration oidag125.gif

This section contains these topics:

• Scenario #1: The Included Naming Context in One Naming Context Object Is a Subtree of the Included Naming Context in Another Naming Context Object

• Scenario #2: The Included Naming Context in One Naming Context Object Is a Subtree of An Excluded Naming Context in Another Naming Context Object

• Reserved Naming Contexts and Attributes

• Optimization of Partial Replication for Better Performance

Scenario #1: The Included Naming Context in One Naming Context Object Is a Subtree of the Included Naming Context in Another Naming Context Object

To use an example, suppose that you have a partial replication scenario in which the included naming context in Naming Context Object #2 is itself a subtree of the included naming context in Naming Context Object #1.

Naming Context Object #1

cn=namectx001,
cn=replication namecontext,
orclagreementid=unique_identifier_of_the_replication_agreement,
orclreplicaid=unique_identifier_of_the_supplier,
cn=replication configuration,

orclincludednamingcontexts: cn=mycompany

Naming Context Object #2

cn=namectx002,
cn=replication namecontext,
orclagreementid=unique_identifier_of_the_replication_agreement,
orclreplicaid=unique_identifier_of_the_supplier,
cn=replication configuration

orclincludednamingcontexts: cn=hr,c=us,cn=mycompany
orclexcludednamingcontexts: cn=users,cn=hr,c=us,cn=mycompany
orclexcludedattributes: userpassword

In this scenario, the naming context that is replicated is the highest one specified in the orclincludednamingcontexts attribute. Any excluded naming contexts are not replicated. To use our example, all changes under the subtree cn=mycompany--except cn=users,cn=hr,c=us,cn=mycompany--are replicated. The attribute userpassword is excluded from all changes replicated under cn=hr,c=us,cn=mycompany.

Scenario #2: The Included Naming Context in One Naming Context Object Is a Subtree of An Excluded Naming Context in Another Naming Context Object

To use an example, suppose that you have a partial replication scenario in which the excluded naming context in Naming Context Object #4 is a subtree of the excluded naming context defined in Naming Context Object #3.

Naming Context Object #3

cn=namectx001,cn=replication namecontext,
orclagreementid=identifier,orclreplicaid=supplier,cn=replication configuration

orclincludednamingcontexts: cn=mycompany
orclexcludednamingcontexts: cn=us,cn=mycompany

Naming Context Object #4

cn=namectx002,cn=replication 
namecontext,orclagreementid=identifier,orclreplicaid=supplier,cn=replication 
configuration

orclincludednamingcontexts: cn=hr, c=us,cn=mycompany
orclexcludednamingcontexts: cn=users,cn=hr,c=us,cn=mycompany
orclexcludedattributes: userpassword

In this scenario, the included naming context specified in Naming Context Object #4 is not replicated. That naming context is a subtree of a specified excluded naming context in Naming Context Object #3. In this case, Naming Context Object #4 is ignored, and no changes under cn=hr,c=us,cn=mycompany are replicated.

Rules for Managing Naming Contexts and Attributes

Reserved Naming Contexts and Attributes

The following naming contexts cannot be replicated:

orclagreementid=000001,cn=replication configuration
cn=subconfigsubentry
cn=Oracle Internet Directory
cn=subregistrysubentry

The following naming contexts cannot be excluded from replication:

cn=catalogs
cn=subschemasubentry
cn=orclshemaversion
cn=replication configuration

The following attributes cannot be excluded from replication whether they are mandatory or optional.

orclguid
creatorsname
createtimestamp
cn
dn
attributetypes
objectclasses
objectclass
orclindexedattribute
orclproductversion

Other Attributes That Cannot Be Excluded from Replication

You cannot exclude mandatory attributes from replication. For example, suppose that you have an object class named my_object_class, which includes the following attributes: mandatory_attribute_1, optional_attribute_1, and optional_attribute_2. In this case, you cannot exclude from replication mandatory_attribute_1.

Naming attributes are always replicated even if you specify them for exclusion from replication.

Optimization of Partial Replication for Better Performance

If not carefully planned, partial replication can degrade performance of the replication process. For example, the definition of naming contexts in Naming Context Object #5 decreases performance as compared to that in Naming Context Object #6.

Naming Context Object #5

In this naming context object, there are two naming context objects in partial replication.

cn=namectx001,cn=replication 
namecontext,orclagreementid=identifier,orclreplicaid=supplier,cn=replication 
configuration
orclincludednamingcontexts: cn=mycompany
orclexcludednamingcontexts: c=europe,cn=mycompany
orclexcludedattributes: userpassword

Naming Context Object #6

cn=namectx002,cn=replication 
namecontext,orclagreementid=<id>,orclreplicaid=<supplier>,cn=replication 
configuration
orclincludednamingcontexts: cn=hr, c=us,cn=mycompany
orclexcludednamingcontexts: cn=users,cn=hr, c=us,cn=mycompany
orclexcludedattributes: userpassword

If these two naming context objects are defined, then all changes under cn=mycompany are replicated--except cn=europe,c=mycompany and cn=users,cn=hr,c=us,cn=mycompany. The attribute userpassword is filtered out. However, as you can see in Naming Context Object #7, you can develop a single naming context object that fulfills the same requirement, and that avoids unnecessary performance degradation in partial replication.

Naming Context Object #7

cn=namectx001,cn=replication 
namecontext,orclagreementid=identifier,orclreplicaid=supplier,cn=replication 
configuration
orclincludednamingcontexts: cn=mycompany
orclexcludednamingcontexts: c=europe,cn=mycompany
orclexcludednamingcontexts: cn=users,cn=hr, c=us,cn=mycompany
orclexcludedattributes: userpassword