Oracle 21c New Feature - Object Activity Tracking System (OATS)

Oracle 21c introduced the Object Activity Tracking System (OATS).  OATS can track various activities associated with database objects by taking periodic snapshots of statistics like scans, inserts, updates, deletes, truncations, etc.

The initial release of OATS only tracks tables and materialized views.  It is planned to eventually track columns, partitions, indexes, and zone maps (ref).

Internally, the OATS is used by several programs within the Oracle 21c database.  For example: the Automatic Materialized Views feature introduced in 21c uses statistics collected by OATS.

In terms of monitoring OATS, the view DBA_ACTIVITY_TABLE shows the usage data captured within each snapshot.  You might notice the number of times a table scan ran against each table in the past 15 minutes, or other such metrics.

The API for OATS is the PL/SQL package DBMS_ACTIVITY.  It allows you to customize the capture interval, snapshot retention period, and space limits and to create and delete snapshots.  For example: you could configure OATS to take a snapshot every 30 minutes, retain the snapshot for 10 days, and to keep at least 15% space free for new snapshots.  However, according to the Oracle documentation, they recommend against changing any of the default values since it could negatively impact OATS' internal clients like the Automatic Materialized Views feature.

For more information about OATS see the Oracle online documentation (ref).

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