We are having multiple performance related issues on our FTS installation

(From the Oracle Documentation from the version used in the deployment)

13.2 Managing Automatic Optimizer Statistics Collection

Oracle recommends that you enable automatic optimizer statistics collection.

In this case, the database automatically collects optimizer statistics for tables with absent or stale statistics.

If fresh statistics are required for a table, then the database collects them both for the table and associated indexes.

Automatic collection eliminates many manual tasks associated with managing the optimizer.

It also significantly reduces the risks of generating poor execution plans because of missing or stale statistics.

Automatic optimizer statistics collection calls the DBMS_STATS.GATHER_DATABASE_STATS_JOB_PROC procedure. This internal procedure operates similarly to the DBMS_STATS.GATHER_DATABASE_STATS procedure using the GATHER AUTO option. The main difference is that GATHER_DATABASE_STATS_JOB_PROC prioritizes database objects that require statistics, so that objects that most need updated statistics are processed first, before the maintenance window closes.

This section contains the following topics:

Enabling and Disabling Automatic Optimizer Statistics Collection

Considerations When Gathering Statistics

13.2.1 Enabling and Disabling Automatic Optimizer Statistics Collection

The automated maintenance tasks infrastructure (known as AutoTask) schedules tasks to run automatically in Oracle Scheduler windows known as maintenance windows. By default, one window is scheduled for each day of the week. Automatic optimizer statistics collection runs as part of AutoTask and is enabled by default to run in all predefined maintenance windows.

If for some reason automatic optimizer statistics collection is disabled, then you can enable it using the ENABLE procedure in the DBMS_AUTO_TASK_ADMIN package:

BEGIN
DBMS_AUTO_TASK_ADMIN.ENABLE(
client_name => 'auto optimizer stats collection',
operation => NULL,
window_name => NULL);
END;
/

Please note specifically "It also significantly reduces the risks of generating poor execution plans because of missing or stale statistics."

Please note in later versions of Oracle this setting is on by default and has been enriched to perform real time statistic gathering.
 

No Optimizer Statistics were being generated.