CACHE PAGE RETENTION BASED ON PAGE COST

A method for retaining data pages in a cache is disclosed. In one embodiment, such a method stores multiple data pages in a cache. The method calculates, for each data page, a cost associated with promoting the data page from persistent storage media to the cache. The cost takes into account any data transformations (decryption, decompression, etc.) that are needed to promote the data page from the persistent storage media to the cache. In certain embodiments, the cost is represented as a score that is assigned to each data page. The method retains each data page in the cache for an amount of time that is related to its cost, such that data pages with a higher cost are retained in the cache longer than data pages with a lower cost. A corresponding apparatus and computer program product are also disclosed.