What is Replay Delete?
Because storage containers are reorganized as part of the Tuple Mover, recovery, refresh, and rebalance operations, the position of deleted records may change in the newly created storage container. In Vertica, a delete vector tracks the position of a deleted record in a storage container and tracks the commit epoch of when the record was deleted. The process of rebuilding delete vectors to adapt to the movement of records across storage containers is known as replay delete. Vertica has two algorithms that perform the replay delete operation.
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https://my.vertica.com/kb/Replay-Delete ... eletes.htm