Describes Autonomous Database commands to run when you need to gather optimizer statistics or enable optimizer hints.
Managing Optimizer Statistics with Transaction Processing and JSON Database Workloads
Autonomous Database gathers optimizer statistics automatically so that you do not need to perform this task manually and this helps to ensure your statistics are current. Automatic statistics gathering is enabled in Autonomous Database and runs in a standard maintenance window.
The automatic statistics gathering maintenance window is different than the maintenance window on the Oracle Cloud Infrastructure console. The Oracle Cloud Infrastructure maintenance window shows system patching information.
For more information on automatic statistics gathering maintenance window times and automatic optimizer statistics collection, see Database Administrator’s Guide.
For more information on optimizer statistics see SQL Tuning Guide.
Managing Optimizer Hints with Transaction Processing and JSON Database Workloads
Autonomous Database with
Transaction Processing and JSON Database workloads honors optimizer hints and
PARALLEL hints in SQL statements by default. You can disable
optimizer hints by setting the parameter
TRUE at the session or system level using
ALTER SYSTEM. For example, the following command
disables hints in your session:
ALTER SESSION SET OPTIMIZER_IGNORE_HINTS=TRUE;
You can also disable
PARALLEL hints in your SQL statements
the session or system level using
ALTER SESSION or
ALTER SESSION SET OPTIMIZER_IGNORE_PARALLEL_HINTS=TRUE;