Abstract: Disclosed is a technique for managing items in a memory store. A “free-space size threshold” is set for the memory store. An age parameter is also set. When the amount of free space in the store decreases below the threshold, space in the store is freed up by removing memory items. Memory items older than specified by the age parameter are also removed. A “chain” of memory stores can be implemented. When a memory item is removed from the first store, it is added to the second store and so on. The techniques of the present invention can be implemented in each store in the chain, or the stores can use different memory management techniques.

Abstract: Disclosed is a technique for managing memory items in a cache. An “age-lock” parameter is set to protect the newer memory items. When an incoming memory item (such as a history block header) is to be added to the cache, the amount of free space in the cache is checked. If there is insufficient free space for the incoming memory item, then space is freed up by removing memory items from the cache. No memory items protected by the age-lock parameter are removed. Of the older items, the selection for removal follows any of a number of well know cache management techniques, such as the “least recently used” algorithm. A “maximum size” parameter can be set for the cache. If the cache exceeds this maximum size, then free space is released and memory items are removed to decrease the cache size.