Sun Directory Server Enterprise Edition 7.0 Reference

How Directory Server Performs Updates by Using the Cache

In Figure 8–3, individual lines represent threads that access different levels of memory. Broken lines represent probable bottlenecks to minimize through effective tuning of Directory Server.

Figure 8–3 How Directory Server Performs Updates

Figure illustrates how Directory Server manages updates.

The figure does not show the impact of the internal base search performed to get the entry for update.

    Directory Server processes updates in the following stages.

  1. Directory Server performs a base DN search to retrieve the entry, or to update or verify the entry in the case of an add operation that it does not already exist.

  2. Directory Server updates the database cache and any indexes affected.

    If data affected by the change have not been loaded into the database cache, this step can result in disk activity while the relevant data are loaded into the cache.

  3. Directory Server writes information about the changes to the transaction log and waits for the information to be flushed to disk, which happens periodically, at each checkpoint. Directory Server database files are thus updated during the checkpoint operation, not for each write.

  4. Directory Server formats and copies the updated entry to the entry cache for the suffix.

  5. Directory Server returns an acknowledgement of successful update to the client application.