When Adaptive Server has no user tasks to process, the housekeeper wash task and the housekeeper chores task automatically begin writing dirty buffers to disk and performing other maintenance tasks. These writes are done only by the housekeeper wash task during the server’s idle cycles, and are known as free writes. They result in improved CPU utilization and a decreased need for buffer washing during transaction processing. They also reduce the number and duration of checkpoint spikes (times when the checkpoint process causes a short, sharp rise in disk writes).
Another housekeeper task is housekeeper garbage collection, which operates at the priority level of the ordinary user. It cleans up data that was logically deleted and resets the rows so the tables have space again.
