There are two forms of garbage collection, lazy and aggressive. These terms describe two distinct tests for finding empty pages.
Lazy garbage collection refers to an inexpensive test to find empty pages. This test may not be effective during long-running transactions, and empty pages may accumulate. Lazy garbage collection is inexpensive to use, but can lower performance, which is affected by the fragmentation of allocated table space, and by the accumulation of empty pages that must be evaluated during queries.
Aggressive garbage collection refers to a sophisticated test for empty pages. This test is more expensive than the lazy garbage collection test, because it checks each deleted row in a page to determine whether the deleted transactions are committed.
Use the enable housekeeper GC configuration parameter to configure the delete command and the housekeeper garbage collection task for aggressive or lazy garbage collection.
The aggressive housekeeper garbage collection self-tunes the frequency with which the housekeeper garbage collection task examines the housekeeper list, so that the frequency of examination matches the rate at which the application generates empty pages.
