Database Statistics Basic Tuning Considerations

22-10 Oracle Fusion Middleware Performance and Tuning Guide operations. The 2ndlevel subtype, which is applicable only to compare operation, sets the number of in-memory cache containers for information about the users whose userpassword is compared and tracked when detailed compare operation statistics is programmed. The default value of both subtypes is 256. The appropriate values for these subtypes depend on the number of users in your environment and the number of applications used to access the directory, as follows: ■ In a deployment where several applications perform operations on behalf of a large number of end users, set 1stlevel proportional to the number of applications, plus a few hundred more for end users directly accessing the directory. Then set 2ndlevel proportional to the number of end users. ■ In a deployment where end users themselves perform the operations, set 1stlevel proportional to the number of end users, then set 2ndlevel to a small value, such as 25. ■ A typical proportional value is one fifth. Proportions between one tenth and one half are reasonable in most environments. If your deployment requires it, set the values for orcloptracknumelemcontainers only when security events collection is turned on.

22.5 Low-Priority Tuning Considerations

This section describes attributes that can sometimes improve performance, but are considered low-priority.

22.5.1 Number of Entries to be Returned by a Search

The attribute orclsizelimit controls the maximum number of entries to be returned by a search. The default value is 10000. Setting it very high impacts server performance. It also plays a role in limiting the maximum number of changelogs the replication server can process at a time. See Section 22.12.3, Modifying Attributes by Using ldapmodify.

22.5.2 Enabling the Group Cache

The instance-specific subentry attribute orclenablegroupcache controls whether privilege groups and ACL groups are cached. Using this cache can improve the performance of access control evaluation for users. Use the group cache when a privilege group membership does not change frequently. If a privilege group membership does change frequently, then it is best to turn off the group cache. It is important to note that computing a group cache may affect performance. The default is 1 enabled. Change to 0 zero to disable. See Section 22.12.3, Modifying Attributes by Using ldapmodify.

22.5.3 Timeout for Write Operations

When an LDAP client initiates an operation, then does not respond to the server for a configured number of seconds, the server closes the connection. The number of seconds is controlled by the orclnwrwtimeout attribute of the instance-specific configuration entry. The default is 30 seconds. Oracle Internet Directory Performance Tuning 22-11 You can modify orclnwrwtimeout by using Fusion Middleware Control or the command line. See Section 22.12.1, Modifying Instance-Specific Attributes by Using Fusion Middleware Control.

22.6 Specific Use Cases

This section describes some specific use cases that require additional tuning, in addition to Section 22.3, Basic Tuning Considerations

22.6.1 Bulk Load Operation

If you are planning a large bulkload operation, make the following changes: ■ Set the database initialization parameter pga_aggregate_target to 1-4GB for the duration of the operation, if sufficient RAM is available. ■ Increase the database temporary tablespace before loading a large number entries. You need about 1G of temporary tablespace per million entries being loaded. You can free up the tablespace after the operation.

22.6.2 Bulk Delete Operation

If you are planning a large bulkdelete operation, perform the following tasks: ■ Ensure that the database initialization parameter sga_target are tuned as described in Section 22.3.1, Database Parameters. ■ Set the database initialization parameter log_buffer to 10M. This can provide additional performance benefit. ■ Ensure that you have at least three database redo log files with at least 100MB. ■ Ensure that the undo tablespace is at least 1 GB in total size. ■ Follow the recommendations about redo logs and undo tablespace in the next section, Section 22.6.3, High LDAP Write Operations Load.

22.6.3 High LDAP Write Operations Load

If you have a high LDAP write operations load, or if you perform many bulkdelete operations, consider tuning the following values: ■ Increase the size or number of the database redo log files so that the total size is 1000-1500 MB. Other considerations affect the total size of redo logs. ■ Depending on how the disks are configured, it might be beneficial to isolate the redo log files to a dedicated set of disks. ■ Increase the undo tablespace size by adding data files to this tablespace. For most deployments, 2-4 GB should suffice. ■ Do not use the Oracle Internet Directory server entry cache. See Section 22.4.6, Server Entry Cache. ■ If neither Oracle Internet Directory replication nor DIP is deployed, disable change log generation. See Section 22.4.1, Replication or Oracle Directory Integration Platform. Table 22–6 summarizes the redo log and undo tablespace recommendations provided in this section.