Oracle Database 11 g - Online Public Access Catalog

12 CHAPTER 1 ■ INSTALLING, UPGRADING, AND MANAGING CHANGEThe db_ultra_safe_parameter can take three values—off, data only, and data and index.By default, the db_ultra_safe parameter is set to off, meaning that any values you set for anyof the three parameters won’t be overridden. If you set the db_ultra_safe parameter value todata only, the following will be true:• db_block_checking will be set to medium.• db_lost_write_protect will be set to typical.• db_block_checksum will be set to full.If you set the db_ultra_safe parameter value to data and index, the following will be true:• db_block_checking will be set to full.• db_lost_write_protect will be set to typical.• db_block_checksum will be set to full.Security-Related ParametersThere are two important security-related initialization parameters that are new in OracleDatabase 11g. The first parameter, sec_case_sensitive_logon, lets you enable and disablepassword case-sensitivity in the database. By default, password case-sensitivity is enabled inOracle Database 11g.The other new security-related initialization parameter is the parameter sec_max_failed_login_attempts, which specifies the maximum number of times a client can make a connectionattempt to a server. The default value of this parameter is 10.Please see Chapter 5 for more details about the new case-sensitive password feature aswell as the sec_max_failed_login_attempts parameter.Optimizer-Related ParametersThere are several important new optimizer-related initialization parameters that are intendedto support powerful new features such as SQL Plan Management, private statistics, and invisibleindexes. We discuss all these features in subsequent chapters and merely introduce therelevant new initialization parameters in this section.Oracle Database 11g replaces the old plan stability feature with the new SQL Plan Managementfeature. A change in the execution plan of an important SQL statement can potentiallydegrade performance. To avoid this performance degradation, the database selects optimalSQL plan baselines and prevents the optimizer from changing the execution plan of a statementuntil the new plan is found to be definitely superior to the existing SQL baseline plan(lower cost). You can enable automatic SQL plan capture so the database can capture andmaintain SQL plan history using information from the optimizer.By default, automatic plan capture is disabled, and you can enable it by setting theoptimizer_capture_sql_plan_baselines parameter to true. Chapter 4 contains a detaileddiscussion of the SQL Plan Management feature.