Heat Map is an Oracle Database 12c feature that stores system-generated data usage statistics at the row and segment levels – information that can be used to automate the compression and movement of data in order to reduce storage costs, improve performance and optimize Oracle Database storage. Heat Map, used in conjunction with Automatic Data Optimization can automate compression and storage policies based on the usage of the data.
1. Segment level Heat Map tracks the time of last modification and access of tables and partitions.
2. Row level Heat Map shows modification times at the row level.
Heat Map, once enabled, and automatically collects segment and row level statistics that can be used to define compression and storage policies which will be automatically maintained throughout the lifecycle of the data. Heat Map skips internal access done for system tasks -- automatically excluding Stats Gathering, DDLs or Table Redefinitions.
How to Enable Heat Map:
alter system set heat_map = on scope=both;
1. Segment level Heat Map tracks the time of last modification and access of tables and partitions.
2. Row level Heat Map shows modification times at the row level.
Heat Map, once enabled, and automatically collects segment and row level statistics that can be used to define compression and storage policies which will be automatically maintained throughout the lifecycle of the data. Heat Map skips internal access done for system tasks -- automatically excluding Stats Gathering, DDLs or Table Redefinitions.
How to Enable Heat Map:
alter system set heat_map = on scope=both;
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