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2.2. Tracking Configuration History
Data from the Red Hat Virtualization History Database (called
ovirt_engine_history) can be used to track the
The ETL service,
ovirt-engine-dwhd, tracks three types of changes:
- A new entity is added to the engine database - the ETL Service replicates the change to the ovirt_engine_history database as a new entry.
- An existing entity is updated - the ETL Service replicates the change to the ovirt_engine_history database as a new entry.
- An entity is removed from the engine database - A new entry in the ovirt_engine_history database flags the corresponding entity as removed. Removed entities are only flagged as removed.
The configuration tables in the ovirt_engine_history database differ from the corresponding tables in the engine database in several ways. The most apparent difference is they contain fewer configuration columns. This is because certain configuration items are less interesting to report than others and are not kept due to database size considerations. Also, columns from a few tables in the engine database appear in a single table in ovirt_engine_history and have different column names to make viewing data more convenient and comprehensible. All configuration tables contain:
history_idto indicate the configuration version of the entity;
create_datefield to indicate when the entity was added to the system;
update_datefield to indicate when the entity was changed; and
delete_datefield to indicate the date the entity was removed from the system.