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    High contention transaction processing prototype for e-commerce workloads
    ZHANG Shuyan, WANG Qingshuai, ZHANG Rong
    Journal of East China Normal University(Natural Science)    2020, 2020 (5): 1-9.   DOI: 10.3969/j.issn.1000-5641.202091005
    Abstract363)   HTML1072)    PDF (829KB)(156)      
    Modern multi-core main-memory databases still cannot achieve ideal performance under high contention. Throughput is considered to be choked by concurrent transactions trying to modify the same data. These transactions contend for the same resources and must be executed serially in a traditional database. Unfortunately, e-commerce workloads often meet with high contentions due to promotions. In this paper, we optimize the transaction processing scheme for high contention e-commerce workloads from two aspects. First, prefiltering is designed to filter invalid modifications to the databases, which can mitigate the contention for locks. Second, if a large number of writes are similar, we propose to do lock sharing among similar writes. We implement a prototype of our proposed system, Filmer, to demonstrate the idea. Extensive experiments have shown that filtering and merging improve efficiency in handling high contention e-commerce workloads.
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    Global transaction log of a multi-master cloud database
    WEI Xiaoxian, LIU Wenxin, CAI Peng
    Journal of East China Normal University(Natural Science)    2020, 2020 (5): 10-20.   DOI: 10.3969/j.issn.1000-5641.202091002
    Abstract366)   HTML45)    PDF (814KB)(106)      
    With the prevalence of cloud computing, users’ requirements for cloud databases are becoming increasingly complex. The current write-once-read-many cloud database system, based on shared storage, cannot support the dynamic expansion of write performance. Multiple master nodes provide write services simultaneously, which can cause cross-node read and write conflicts, eventually leading to inconsistencies in the cache of multiple master nodes. For this problem, optimistic conflict detection based on globally ordered transaction logs can detect cross-node transaction conflicts, roll back conflicting transactions, and maintain the isolation level and consistency of the overall system. By broadcasting and replaying the global orderly transaction log, moreover, the modification of the master node can be synchronized to the remaining nodes to ensure the independent service capability of each individual node. This multi-master cache consistency solution based on global transaction logs is implemented on the open source database MySQL, and the impact on system performance is verified through experiments.
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    Research and implementation of a smart automatic contract generation method for Ethereum
    GAO Yichen, ZHAO Bin, ZHANG Zhao
    Journal of East China Normal University(Natural Science)    2020, 2020 (5): 21-32.   DOI: 10.3969/j.issn.1000-5641.202091015
    Abstract704)   HTML56)    PDF (941KB)(268)      
    Smart contracts based on Ethereum have been widely used across various fields. The programming of smart contracts, however, requires professional developers with expertise in a special programming language; in other words, the developers must have professional domain knowledge in addition to programming ability. In this paper, a method for the automated generation of smart contracts for specific domains is proposed with the aim addressing the programming friendliness of smart contracts. The paper introduces cluster analysis of smart contracts and establishes the basic functional code for transactional type smart contracts. MFC is used to link the generated code with UI control and provide users with a friendly smart contract programming page; hence, the automatic generation of smart contracts is realized, thereby reducing the difficulty and cost of contract programming. Finally, a case study is presented to verify the availability of the generated smart contract.
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