RAC Performance Tuning Goal

• Optimize connection management, ensure that the middle tier and programs that connect to the database are efficient in connection management and do not log on or off repeatedly
• Tune the SQL using the available tools such as ADDM and SQL Tuning Advisor
• Ensure that applications use bind variables, cursor sharing was introduced to solve this problem
• Use packages and procedures (because they are compiled) in place of anonymous PL/SQL blocks and big SQL statements
• Use locally managed tablespaces and automatic segment space management to help performance and simplify database administration
• Use automatic undo management and temporary tablespace to simplify administration and increase performance
• Ensure you use large caching when using sequences, unless you cannot afford to lose sequence during a crash
• Avoid using DDL in production, it increases invalidations of the already parsed SQL statements and they need to be recompiled
• Partion tables and indexes to reduce index leaf contention (buffer busy global cr problems)
• Optimize contention on data blocks (hot spots) by avoiding small tables with too many rows in a block

Now we can review RAC specific best practices

• Consider using application partitioning (see below)
• Consider restricting DML-intensive users to using one instance, thus reducing cache contention
• Keep read-only tablespaces away from DML-intensive tablespaces, they only require minimum resources thus optimizing Cache Fusion performance
• Avoid auditing in RAC, this causes more shared library cache locks
• Use full tables scans sparingly, it causes the GCS to service lots of block requests, see table v$sysstat column "table scans (long tables)"
• if the application uses lots of logins, increase the value of sys.audsess$ sequence