Gather Schema Statistics

Gurtej asked this question: While submitting gather schema stats for APPS ...what should be the estimate percent and degree should be ? How should GSS be scheduled in Production. Currently it is scheduled like this:
APPS, 10, 8, NOBACKUP, , LASTRUN, GATHER, , Y

Here's the answer gleaned from various articles in My Oracle Support:

There is no set schedule for gathering schema statistics. On some systems the program should be run weekly. On other systems once per month will be often enough. The schedule will vary greatly depending on the amount and nature of the data and how often the data changes.

It will be necessary to try different schedules over time and monitor performance to determine the most effective schedule.

As a general rule, run Gather Schema Statistics under the following circumstances:

1. After there has been a significant change in data in either content or volume.

2. After importing data.

3. Any time end-users notice a deterioration in performance in routine day-to-day business transactions or when running concurrent programs.

Estimate Percentage / Modification threshold defines the percentage which should be used to initiate gather stats for those objects which have actually changed beyond the threshold. The default is 10% (i.e. meaning any table which has changed via DML more than 10%, stats will be collected, otherwise it will be skipped

Further Reading: Tuning All layers of E-Business Suite:

OracleNavigate.Responsibility was not found on this server

We got this error in one of the instances cloned freshly on clicking on the
System Administration responsibility:

Not Found
The requested URL /pls/$ORACLE_SID/OracleNavigate.Responsibility was not found on this server.

Fix:

Change Self Service Personal Home Page mode profile option on site level to Framework Only