6. Directory Server Replication > External Change Log > Porting Applications that Rely on Other Change Logs |
2. The Directory Server Access Control Model
3. Understanding the Directory Server Schema
4. Directory Server Index Databases
5. Understanding Directory Server Plug-Ins
6. Directory Server Replication
Overview of the Directory Server Replication Architecture
Basic Replication Architecture
Directory Server Change Processing
Historical Information and Conflict Resolution
What is a Replication Conflict?
Purging Historical Information
Schema Replication Architecture
Replication Status Definitions
Full Update Status and Bad Generation ID Status
Safe Read Mode and Replication Groups
Assured Replication Connection Algorithm
Assured Replication and Replication Status
Assured Replication Monitoring
Fractional Data Set Identification
Fractional Replication Filtering
Fractional Replication and Local Operations
How the External Change Log Works
Porting Applications that Rely on Other Change Logs
Differences Between the ECL and the LDAP Change Log Draft
API for Compatibility With the LDAP Change Log Draft and the Sun DSEE Retro Change Log
Limitations of the Compability API
The Sun DSEE RCL specifies that the target entry unique ID is stored in the targetuniqueid attribute. The format of this attribute value is specific to Sun DSEE. The replicationcsn attribute also has a value that is specific to Sun DSEE.
The Sun DSEE RCL supports configurations with a list of attributes of the entry when an entry has been deleted. This is not supported in the Sun OpenDS Standard Edition ECL but might be supported in a future release.
The Sun DSEE RCL supports the following attributes in the root DSE entry:
The firstchangenumber attribute, which contains the first (oldest) change log index as an integer change number.
This value is updated when the change log is purged. Before connecting to the change log server, an application reads the first change log index and compares it with the change log index that it stored. If the first change log index is more recent than the last change log index stored by the application, the application knows that the changes from the application index to the first change log index will never be returned by the server. They can only be obtained by reading the entries (full resync).
With the Sun OpenDS Standard Edition ECL, this procedure is not required of the application. Instead the Sun OpenDS Standard Edition server does the check and rejects the request when the cookie is too old. For more information, see Using the External Change Log in Sun OpenDS Standard Edition 2.2 Administration Guide.
The lastchangenumber attribute, which contains the latest (newest) change log index as an integer change number.
The Sun OpenDS Standard Edition ECL supports the equivalent feature with the lastExternalChangelogCookie attribute. For more information, see Using the External Change Log in Sun OpenDS Standard Edition 2.2 Administration Guide.
In the Sun DSEE RCL, the external change log and the regular replication change log are different databases. In Sun OpenDS Standard Edition, the two change logs are in the same database. This design decision has several advantages. An additional consequence of this design decision is that Sun DSEE can have two different trim policies (purge delays), while in Sun OpenDS Standard Edition the trim policy is the same.