Patent ID: 8171229
Filing Date: 2012-05-01
Classification: G06F

Abstract:
1. A method for managing free space in a data cache in a central processing unit (CPU) of a database system, in which unused pages are represented in a local free bucket queue, the method comprising: defining a local free bucket queue; determining whether a size of the free bucket queue is one of more than an overflow threshold and less than an underflow threshold, the overflow threshold being set for the free bucket queue during freeing of pages, the underflow threshold being set for the free bucket queue during allocating of pages; determining whether a global free list queue is locked by a locking process; and if the size of the free bucket queue is more than the overflow threshold and if the global free list queue is locked by the locking process, flushing some of the unused pages from the free bucket queue into the global free list queue, the flushing characterizing the freeing of pages, and if the size of the free bucket queue is less than the underflow threshold and if the global free list is locked by the locking process, obtaining, by the free bucket queue, unused pages from the global free list, the obtaining characterizing the allocating of pages.