Intersection of sorted lists is a cornerstone operation in many applications including search engines and databases because indexes are often implemented using different types of sorted structures. At GridDynamics, we recently worked on a custom database for realtime web analytics where fast intersection of very large lists of IDs was a must for good performance. From a functional […]
In web applications, it is a very common task to sort some set of items according to the user-selected criteria and return only the first or N-th page of the sorted result. The page size can be much less than the total number of items, hence it is typically not reasonable to sort the entire set and […]
This post is a second part of Ultimate Sets and Maps for Java. In the first part, we discussed memory-efficient implementations of sets and maps. These data structures efficiently support contains(key) operation. In this part of the article, we discuss more advanced querying: How to efficiently test that a collection of items meets a filtering criteria contains(key1) AND contains(key2) […]
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