Specifying Heap Size Values

2-8 Oracle Fusion Middleware Performance and Tuning Guide Oracle JRockit Mission Control is a suite of tools designed to monitor, manage, profile, and eliminate memory leaks in your Java application without the performance impacts normally associated with these types of tools. For more information on the Oracle JRockit Mission Control see: http:download.oracle.comdocscdE13188_ 01jrockittoolsindex.html ■ Sun JVM The Java™ Platform comes with the following monitoring facilities built-in: ■ Java Virtual Machine Monitoring and Management API ■ JConsole ■ Hprof Tools ■ Logging Monitoring and Management Interface ■ Java Management Extensions JMX For more information on the Java platform monitoring tools, see: http:java.sun.comdevelopertechnicalArticlesJ2SEmonitori ng

2.5 Tune the WebLogic Server

If your Oracle Fusion Middleware applications are using the WebLogic Server, see Top Tuning Recommendations for WebLogic Server in Oracle Fusion Middleware Performance and Tuning for Oracle WebLogic Server.

2.6 Tune Database Parameters

To achieve optimal performance for applications that use the Oracle database, the database tables you access must be designed with performance in mind. Monitoring and tuning the database ensures that you get the best performance from your applications. This section covers the following: ■ Tuning init.ora Database Parameters ■ Tuning Redo Logs Location and Sizing ■ Automatic Segment-Space Management ASSM

2.6.1 Tuning init.ora Database Parameters

The following tables provide common init.ora parameters and their descriptions. Consider following these guidelines to set the database parameters. Ultimately, however, the DBA should monitor the database health and tune parameters based on the need. See the following tables for more information: ■ Table 2–2, Important init.ora Oracle 10g Database Tuning Parameters ■ Table 2–3, Important inti.ora Oracle 11g Database Tuning Parameters Note: Always check the tuning guidelines in your database-specific vendor documentation. For more information on tuning the Oracle database, see the Oracle Database Performance Tuning Guide. Top Performance Areas 2-9 Consider applying Patch Set Release PSR 11.1.0.7 and upgrade the database prior to attempting the following modifications.

2.6.1.1 Initialization Parameters for Oracle 10g

The following table describes several performance-related database initialization parameters for Oracle 10g database. Table 2–2 Important init.ora Oracle 10g Database Tuning Parameters Database Parameter Description DB_BLOCK_SIZE DB_BLOCK_SIZE specifies in bytes the size of Oracle database blocks. The default block size of 8K is optimal for most systems. Set this parameter at the time of database creation. NLS_SORT NLS_SORT specifies the collating sequence for ORDER BY queries. If the value is BINARY, then the collating sequence for ORDER BY queries is based on the numeric value of characters a binary sort that requires fewer system resources. If the value is a named linguistic sort, sorting is based on the order of the defined linguistic sort. Most but not all languages supported by the NLS_ LANGUAGE parameter also support a linguistic sort with the same name. OPEN_CURSORS OPEN_CURSORS specifies the maximum number of open cursors handles to private SQL areas a session can have at once. You can use this parameter to prevent a session from opening an excessive number of cursors. It is important to set the value of OPEN_CURSORS high enough to prevent your application from running out of open cursors. The number varies from one application to another. Assuming that a session does not open the number of cursors specified by OPEN_CURSORS, there is no added performance impact to setting this value higher than actually needed. SESSION_CACHED_CURSORS 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. SESSION_MAX_OPEN_FILES SESSION_MAX_OPEN_FILES specifies the maximum number of BFILEs that can be opened in any session. Once this number is reached, subsequent attempts to open more files in the session by using DBMS_LOB.FILEOPEN or OCILobFileOpen may fail. The maximum value for this parameter depends on the equivalent parameter defined for the underlying operating system. JOB_QUEUE_PROCESSES JOB_QUEUE_PROCESSES specifies the maximum number of processes that can be created for the execution of jobs. It specifies the number of job queue processes per instance. LOG_BUFFER LOG_BUFFER specifies the amount of memory in bytes that Oracle uses when buffering redo entries to a redo log file. Redo log entries contain a record of the changes that have been made to the database block buffers. The LGWR process writes redo log entries from the log buffer to a redo log file. UNDO_MANAGEMENT UNDO_MANAGEMENT specifies which undo space management mode the system should use. When set to AUTO, the instance starts in automatic undo management mode. In manual undo management mode, undo space is allocated externally as rollback segments.