What is Preview Versions for Autonomous Database

A first preview is not exactly a pleasant experience for producers, directors and actors. In the IT world, it is exactly the opposite: DBAs can use the new version of the database before it becomes mainstream.

The “Preview Versions for Autonomous Database” has been available since mid-October 2019. The current preview version of Autonomous Database is Oracle Database 19c. More precisely, the version is 19.4.0.

Databases provisioned or cloned with a preview version display the end date of the preview period at the top of the Autonomous Database details page in the Oracle Cloud Infrastructure Console.

Note that the preview for my database below will end on December 2, 2019. All resources created with the preview will be terminated at the end of the preview period.

The basis details of preview versions for Autonomous Database can be found in the Oracle documentation.

Connecting to the preview database is as to a standard ADB:

Here are some of the default settings in Oracle Database Preview Version 19.4.0 for Autonomous Database:

Real-Time Statistics: Enabled by default
– Oracle automatically gathers online statistics during conventional DML operations
– By gathering some statistics automatically during DML operations, the database augments the statistics gathered by DBMS_STATS
– Fresh statistics enable the optimizer to produce more optimal plans
– EXEC DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO; forces the database to write optimizer statistics to the data dictionary
– NO_GATHER_OPTIMIZER_STATISTICS prevents the collection of real-time statistics

High-Frequency Automatic Optimizer Statistics Collection: Enabled by default
– High-Frequency Automatic Optimizer Statistics Collection complements the standard automatic statistics collection job
– By default, the high-frequency statistics collection occurs every 15 minutes 
– Turn on/off: EXEC DBMS_STATS.SET_GLOBAL_PREFS(‘AUTO_TASK_STATUS’,’ON’);
– Change the default period: EXEC DBMS_STATS.SET_GLOBAL_PREFS(‘AUTO_TASK_INTERVAL’,’300’);
– Monitor: DBA_AUTO_STAT_EXECUTIONS
– The high-frequency automatic statistics task will not start during the maintenance window

SQL Quarantine: Disabled and not supported in Autonomous Database
– Check ORA-56955: quarantined plan used for details on SQL Quarantine

High-Frequency SQL Plan Management Evolve Advisor Task: Enabled by default
– High-Frequency Automatic Optimizer Statistics Collection complements the standard automatic statistics collection job
– By default, the high-frequency statistics collection occurs every 15 minutes 
– Turn on/off: EXEC DBMS_STATS.SET_GLOBAL_PREFS(‘AUTO_TASK_STATUS’,’ON’);
– Change the default period: EXEC DBMS_STATS.SET_GLOBAL_PREFS(‘AUTO_TASK_INTERVAL’,’300’);
– Monitor: DBA_AUTO_STAT_EXECUTIONS
– The high-frequency automatic statistics task will not start during the maintenance window

Automatic Indexing: Disabled by default
– Check Automatic Indexing in 19c for more details on Automatic Indexing

New 19c spfile parameters
– All 6 new init.ora parameters in 19c are set to their default values (click on the links below to see the values):

ADG_REDIRECT_DML
DATA_GUARD_MAX_IO_TIME
DATA_GUARD_MAX_LONGIO_TIME
ENABLE_IMC_WITH_MIRA
LOB_SIGNATURE_ENABLE
MAX_DATAPUMP_PARALLEL_PER_JOB

Preview is not free of charge. Preview provides you test/development capacity and capabilities so it is charged identically to production environments. Also, preview is not available for free service instances.

Preview instances are fully supported but should not be used for production purposes.

At the end, you may want to check out the new static data dictionary views in 19c:

• ALL_TRIGGERS_AE, DBA_TRIGGERS_AE, and USER_TRIGGERS_AE
• DBA_AUTO_INDEX_CONFIG
• DBA_AUTO_STAT_EXECUTIONS
• DBA_PDB_SNAPSHOTFILE
• DBA_RAT_CAPTURE_SCHEMA_INFO
• DBA_REGISTRY_BACKPORTS
• DBA_SQL_QUARANTINE

and also the new dynamic performance views in 19c:

• GV$AQ_PARTITION_STATS and V$AQ_PARTITION_STATS
• GV$ASM_ACFSAUTORESIZE and V$ASM_ACFSAUTORESIZE
• GV$ASM_DBCLONE_INFO and V$ASM_DBCLONE_INFO
• GV$MEMOPTIMIZE_WRITE_AREA and V$MEMOPTIMIZE_WRITE_AREA
• GV$SQL_TESTCASES and V$SQL_TESTCASES