Tuning Redo Logs Location and Sizing Automatic Segment-Space Management ASSM

28-8 Developers Guide for Oracle Application Integration Architecture Foundation Pack

28.2.4 Tuning Redo Logs Location and Sizing

Managing the database IO load balancing is a non-trivial task. However, tuning the redo log options can provide performance improvement for applications running in an Oracle Fusion Middleware environment, and in some cases, you can significantly improve IO throughput by moving the redo logs to a separate disk. The size of the redo log files can also influence performance, because the behavior of the database writer and archiver processes depend on the redo log sizes. Generally, larger redo log files provide better performance by reducing checkpoint activity. It is not possible to provide a specific size recommendation for redo log files, but redo log files in the range of a hundred megabytes to a few gigabytes are considered reasonable. Size your online redo log files according to the amount of redo your system generates. A rough guide is to switch logs at most once every twenty minutes. Set the initialization parameter LOG_CHECKPOINTS_TO_ALERT = TRUE to have\checkpoint times written to the alert file.\The complete set of required redo log files can be created during database creation. After they are created, the size of a redo log size cannot be changed. New, larger files can be added later, however, and the original smaller ones can be dropped. For more information, see Oracle Fusion Middleware Performance and Tuning Guide.

28.2.5 Automatic Segment-Space Management ASSM

For permanent tablespaces, consider using automatic segment-space management. Such tablespaces, often referred to as bitmap tablespaces, are locally managed tablespaces with bitmap segment space management. For backward compatibility, the default local tablespace segment-space management mode is MANUAL. Session_cached_ cursors 200 SESSION_CACHED_CURSORS specifies the number of session cursors to cache. Repeated parse calls of the same SQL statement cause the session cursor for that statement to be moved into the session cursor cache. Subsequent parse calls find the cursor in the cache and do not reopen the cursor. Oracle uses a least recently used algorithm to remove entries in the session cursor cache to make room for new entries when needed. This parameter also constrains the size of the PLSQL cursor cache which PLSQL uses to avoid having to re-parse as statements are re-executed by a user. A starting value of 200 is reasonable for a typical AIA system. TRACE_ENABLED FALSE TRACE_ENABLED controls tracing of the execution history, or code path, of Oracle. Oracle Support Services uses this information for debugging. Although the performance impact incurred from processing is not excessive, you may improve performance by setting TRACE_ ENABLED to FALSE. Table 28–1 Cont. Common init.ora Parameters Dehydration Store Specific Parameter Recommended Setting for Staging and Production Description Tuning Integration Flows 28-9 For more information, see Oracle Database Concepts, Free Space Management and Oracle Database Administrators Guide , Specifying Segment Space Management in Locally Managed Tablespaces.

28.2.6 Changing the Driver Name to Support XA Drivers