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In the big data era, distributed computation is becoming a preferred solution for iterative graph analysis. However, graphs are rapidly growing in size and more importantly, there exist a lot of messages across iterations. For better scalability, many distributed systems keep graph data and message data on disk. Now these systems solely employ either pushing or pulling mode to manage data, but neither can always work well during the entire computation. This is mainly because I/O access patterns are dynamic and complex. This article proposes a hybrid solution. It achieves the optimal performance in different scenarios by dynamically and adaptively switching modes between pushing and pulling. Specifically, we first devise a new block-centric pulling technique. It pulls messages much more I/O-efficiently than the existing vertex-centric pulling mode. We then combine pushing and pulling. For general-purpose, we categorize graph algorithms and accordingly present two seamless switching frameworks. We also design performance prediction components specialized to the two frameworks, to decide how and when we can switch modes. Some optimization strategies are also given to further enhance performance, such as priority scheduling and lightweight fault-tolerance. Extensive experiments against state-of-the-art solutions confirm the effectiveness of our proposals. [ABSTRACT FROM AUTHOR]

Column-oriented stores, known for their scalability and flexibility, are a common NoSQL database implementation and are increasingly used in big data management. In column-oriented stores, a “full-scan” query strategy is inefficient and the search space can be reduced if data is well partitioned or indexed; however, there is no pre-defined schema for building and maintaining partitions and indexes at lower cost. We leverage an accumulative and high-dimensional data model, a sophisticated linearization algorithm, and an efficient query algorithm, to solve the challenge of how a pre-defined and well-partitioned data model can be applied to flexible and time-varied key-value data. We adapt a high-dimensional array as the data model to partition the key-value data without additional storage and massive calculation; improve the Z-order linearization algorithm, which map multidimensional data to one dimension while preserving locality of the data points, for flexibility; efficiently build an expansion mechanism for the data model to support time-varied data. The result is Haery, a column-oriented store, based on a distributed file system and computing framework. In experiments, Haery is compared with Hive, HBase, Cassandra, MongoDB, PostgresXL, and HyperDex in terms of query performance. With results indicating Haery on average performs 4.57x, 4.23x, 3.55x, 1.79x, 1.82x, and 120.6x faster, respectively. [ABSTRACT FROM AUTHOR]