Query plan not in dba_hist_sql_plan

I rely on dba_hist_sql_plan for me to track query performance for each sql_id, however, this time the query plan hash value shows in v$sql, but not recorded in dba_hist_sql_plan, though AWR snapshots are take every 1 hour.

When I open myOracle support ticket, the support engineer told me that "The PHV 1779814119 was first loaded on 2023-08-20/08:36:37, and it's still the current execution plan, while PHV 521264029 was historically used and appears in the view dba_hist_sql_plan

Once there is a new current PHV different than 1779814119 , you will find this in the historical sql plans when it's flushed by the mmon slaves as part of the AWR activities
"

I think that's a wrong statement.

ChatGPT tells me that topNsql of AWR might be the answer, googling on topNsql results in a few findings such as this one below.

I did not test it yet because I do not have DBA permission on the database, so in theory this could be the issue.

 https://ironmandba.wordpress.com/modifying-awr-automatic-snapshot-settings/

Change the number of SQL’s captured -TOPNSQL

I am going to change the settings to capture all the SQL’s in the cache

execute  dbms_workload_repository.modify_snapshot_settings (topnsql => 'MAXIMUM');

The number of SQL statements captured also depends on your statistics_level setting:

When statistics_level=typical, AWR will capture the topnsql.  Without the topnsql set, the default is to capture 30 SQL statements, for a total of 420 per snapshot.

When statistics_level=all, AWR will capture the top 100 SQL for each of the criteria (elapsed time, CPU, disk reads, etc.), for a total of 1400 SQL statements per snapshot.

Top N SQL size -> This can be set to (DEFAULT, MAXIMUM, N).  Specifying DEFAULT will revert the system back to the default behavior of Top 30 for statistics level TYPICAL and Top 100 for statistics level ALL. The number of Top SQL to flush for each SQL criteria (Elapsed Time, CPU Time, Parse Calls, Shareable Memory, Version Count). The value for this setting will not be affected by the statistics/flush level and will override the system default behavior for the AWR SQL collection. The setting will have a minimum value of 30 and a maximum value of 50,000. Specifying NULL will keep the current setting.

SQL> exec dbms_workload_repository.modify_snapshot_settings(retention=>28800, interval=>30, topnsql=>100, dbid=>3970683413);