These are the compliance standard rules for the pluggable database compliance standards. The compliance standards are:
The compliance standard rules for the Configuration Best Practices for Pluggable Database compliance standard follow.
Description: Checks for the use of non-standard initialization parameters.
Severity: Minor Warning
Rationale: Non-standard initialization parameters are being used. These may have been implemented based on poor advice or incorrect assumptions. In particular, parameters associated with SPIN_COUNT on latches and undocumented optimizer features can cause a great deal of problems that can require considerable investigation.
Description: Checks for use of a single control file.
Severity: Critical
Rationale: The control file is one of the most important files in an Oracle database. It maintains many physical characteristics and important recovery information about the database. If you lose the only copy of the control file due to a media error, there will be unnecessary down time and other risks.
Description: Checks if the PGA_AGGREGATE_TARGET initialization parameter has a value of 0 or if WORKAREA_SIZE_POLICY has value of MANUAL.
Severity: Warning
Rationale: Automatic PGA memory management simplifies and improves the way PGA memory is allocated. When enabled, Oracle can dynamically adjust the portion of the PGA memory dedicated to work areas while honoring the PGA_AGGREGATE_TARGET limit set by the DBA.
Description: Checks if the STATISTICS_LEVEL initialization parameter is set to BASIC.
Severity: Critical
Rationale: Automatic statistics collection allows the optimizer to generate accurate execution plans and is essential for identifying and correcting performance problems. By default, STATISTICS_LEVEL is set to TYPICAL. If the STATISTICS_LEVEL initialization parameter is set to BASIC, the collection of many important statistics, required by Oracle database features and functionality, are disabled.
Description: Checks if the STATISTICS_LEVEL initialization parameter is set to ALL.
Severity: Minor Warning
Rationale: Automatic statistics collection allows the optimizer to generate accurate execution plans and is essential for identifying and correcting performance problems. The STATISTICS_LEVEL initialization parameter is currently set to ALL, meaning additional timed OS and plan execution statistics are being collected. These statistics are not necessary and create additional overhead on the system.
Description: Checks if the TIMED_STATISTICS initialization parameter is set to FALSE.
Severity: Critical
Rationale: Setting TIMED_STATISTICS to FALSE prevents time related statistics, for example execution time for various internal operations, from being collected. These statistics are useful for diagnosing and performance tuning. Setting TIMED_STATISTICS to TRUE will allow time related statistics to be collected, and will also provide more value to the trace file and generates more accurate statistics for long-running operations.
The compliance standard rules for the Storage Best Practices for Pluggable Database compliance standard follow.
Description: Checks for dictionary managed tablespaces.
Severity: Minor Warning
Rationale: These tablespaces are dictionary managed. Oracle recommends using locally managed tablespaces, with AUTO segment-space management, to enhance performance and ease of space management.
Description: Checks for users using a permanent tablespace as the temporary tablespace.
Severity: Minor Warning
Rationale: These users use a permanent tablespace as the temporary tablespace. Using temporary tablespaces allows space management for sort operations to be more efficient. Using a permanent tablespace for these operations may result in performance degradation, especially for Real Application Clusters. There is an additional security concern. This makes it possible for users to use all available space in the system tablespace, causing the database to stop working.
Description: Checks for non-system users using SYSTEM or SYSAUX as the default tablespace.
Severity: Minor Warning
Rationale: These non-system users use a system tablespace as the default tablespace. This violation will result in non-system data segments being added to the system tablespace, making it more difficult to manage these data segments and possibly resulting in performance degradation in the system tablespace. This is also a security issue. All Available space in the system tablespace may be consumed, thus causing the database to stop working.
Description: Checks for locally managed tablespaces that are using MANUAL segment space management.
Severity: Minor Warning
Rationale: Automatic segment-space management is a simpler and more efficient way of managing space within a segment. It completely eliminates any need to specify and tune the PCTUSED, FREELISTS and FREELIST GROUPS storage parameters for schema objects created in the tablespace. In a Real Application Cluster environment, there is the additional benefit of avoiding the hard partitioning of space inherent with using free list groups.
Description: Checks for dictionary managed or migrated locally managed tablespaces with non-uniform default extent size.
Severity: Minor Warning
Rationale: Dictionary managed or migrated locally managed tablespaces using non-uniform default extent sizes have been found. This means that the extents in a single tablespace will vary in size leading to fragmentation, inefficient space usage, and performance degradation.
Description: Checks for rollback segments in the SYSTEM tablespace.
Severity: Minor Warning
Rationale: The SYSTEM tablespace should be reserved only for the Oracle data dictionary and its associated objects. It should NOT be used to store any other types of objects such as user tables, user indexes, user views, rollback segments, undo segments, or temporary segments.
Description: Checks for use of less than three redo logs.
Severity: Warning
Rationale: The online redo log files are used to record changes in the database. When archiving is enabled, these online redo logs need to be archived before they can be reused. Every database requires at least two online redo log groups to be up and running. When the size and number of online redo logs are inadequate, LGWR will wait for ARCH to complete its writing to the archived log destination, before it overwrites that log. This can cause severe performance slowdowns during peak activity periods.
Description: Checks for redo log files less than 1 Mb. QUESTION TO REVIEWERS: Spec has 1 Mb (megabit). Should it be 1 MB (megabyte)?
Severity: Critical
Rationale: Small redo logs cause system checkpoints to continuously put a high load on the buffer cache and I/O system.
Description: Checks for tablespaces containing both rollback and data segments.
Severity: Minor Warning
Rationale: These tablespaces contain both rollback and data segments. Mixing segment types in this way makes it more difficult to manage space and may degrade performance in the tablespace. Use of a dedicated tablespace for rollback segments enhances availability and performance.
Description: Checks if the DEFAULT_PERMANENT_TABLESPACE database property is set to a system tablespace.
Severity: Warning
Rationale: If not specified explicitly, DEFAULT_PERMANENT_TABLESPACE is defaulted to the SYSTEM tablespace. This is not the recommended setting. With this setting, any user who is not explicitly assigned a tablespace uses the system tablespace. Doing so may result in performance degradation for the database. This is also a security issue. Non-system users may store data and consume all available space in the system tablespace, thus causing the database to stop working.
Description: Checks for data segments owned by non-system users located in tablespaces SYSTEM and SYSAUX.
Severity: Minor Warning
Rationale: These segments belonging to non-system users are stored in system tablespaces SYSTEM or SYSAUX. This violation makes it more difficult to manage these data segments and may result in performance degradation in the system tablespace. This is also a security issue. If non-system users are storing data in a system tablespace it is possible that all available space in the system tablespace may be consumed, thus causing the database to stop working.
Description: Checks if the DEFAULT_TEMP_TABLESPACE database property is set to a system tablespace.
Severity: Warning
Rationale: If not specified explicitly, DEFAULT_TEMP_TABLESPACE would default to SYSTEM tablespace and this is not a recommended setting. With this setting, any user who is not explicitly assigned a temporary tablespace uses the system tablespace as their temporary tablespace. System tablespaces should not be used to store temporary data. This is also a security issue. Non-system users may store data and consume all available space in the system tablespace, thus causing the database to stop working.