DIverse DatabasE ReplicatiOn - Performance Comparison (DIDERO-PC)

本提案是关于各种数据库复制协议的实验评估。它的目的是比较几种数据库复制协议的性能，这些协议可以防止非崩溃故障，并且基于不同（即不同设计的）数据库管理系统的使用。这些dbms是由不同的供应商开发的，可以是商业的（例如Microsoft SQL Server， Oracle），也可以是开源的产品（例如MySQL， PostgreSQL）。实验评估将使用两种方法进行：基于模型的方法和在“真实”系统的试验台上的直接实验。与使用来自同一供应商的dbms的传统方法相比，不同的数据库复制协议有可能提供更高的可靠性保证（伦敦城市大学软件可靠性中心（CSR）的研究对这一发现做出了重大贡献）。然而，除了实现适当的可靠性水平外，系统设计者和其他DBMS利益相关者还对替代解决方案提供的性能特征感兴趣。事实上，对于许多应用程序，性能是选择过程中的主要标准。在数据库复制协议（包括本提案中研究的协议）之间进行公平而彻底的性能比较，对于系统设计人员在决定哪一种协议最适合集成到他们的系统中时非常有益。这是该提案的主要动机。该项目旨在比较三种数据库复制协议的性能，这些协议可以防止非崩溃故障，并基于不同dbms的使用：我们的DivRep（参考点），SES和Byzantium。具体的性能评估有两个主要目标要实现：目标1 -基于在实验测试平台上使用“真实”系统的评估，即使用复制协议的各自实现以及真实的dbms。-目标2 -基于模型的评估，即每个复制协议以及DBMS资源都用合适的模型（在选择的特定工具中实现）表示，并通过对各自模型的模拟来衡量协议性能。dbms和相关复制协议的性能比较常常仅仅基于使用（合成）基准的比较，在大多数情况下，这些比较并不能反映被测系统的操作概况。此外，仅基于“真实”系统的实验评估进行性能比较所能达到的效果是有限的：人们只能可行地探索有限范围的参数值（如副本数量、读写操作之间的比率等）。相比之下，基于模型的方法提供了更大的灵活性，它以一种实用的方式提供了具有广泛配置参数的评估方法。因此，该提案旨在满足以下目标：-目标3 -提供一种基于模型的数据库复制协议性能评估的通用方法。

This proposal is about experimental evaluation of diverse database replication protocols. It aims at comparing the performance of several database replication protocols, which protect against non-crash failures and are based on use of diverse, i.e. different by design, database management systems (DBMSs). These DBMSs are developed by different vendors, and can be either commercial (e.g. Microsoft SQL Server, Oracle), or open-source products (e.g. MySQL, PostgreSQL). The experimental evaluation will be conducted using two approaches: a model-based approach and a direct experimentation on a testbed with "real" systems.Diverse database replication protocols have a potential of providing higher dependability assurance than traditional approaches that are based on the use of the DBMSs from the same vendor (research from the Centre for Software Reliability (CSR) at City University London has contributed significantly to that finding). However, besides achieving appropriate dependability level, system designers and other DBMS stakeholders are interested in the performance characteristics offered by alternative solutions. For many applications performance is, in fact, the dominant criterion in the selection process.A fair and thorough performance comparison between database replication protocols, including the ones studied in this proposal, is of great benefit to system designers when making decisions about which one is most suitable to integrate in their system. This is the main motivation of the proposal.The project aims at comparing the performance of three database replication protocols which guard against non-crash failures and are based on use of diverse DBMSs: our DivRep (the reference point), SES and Byzantium. There are two main objectives of the particular performance evaluation to be achieved:- Objective 1 - evaluation based on using "real" systems on an experimental testbed, i.e. using respective implementations of the replication protocols together with the real DBMSs.- Objective 2 - model-based evaluation, whereby each replication protocol, as well as DBMS resources, are represented with a suitable model (implemented in a particular tool of choice) and the protocol performance measured by simulation of the respective model.Performance comparison of DBMSs and related replication protocols is too often based only on the comparison that uses (synthetic) benchmarks, which in most cases do not reflect the operational profile of the system under test. In addition, there are limits to what one can achieve with performance comparison based only on experimental evaluation with "real" systems: one can feasibly explore only a limited range of parameter values (such as number of replicas, ratio between read and write operations, etc). In contrast, model-based approach offers greater flexibility by providing means for evaluation with a wide range of configuration parameters in a practical manner. Therefore, the proposal aims at satisfying the following objective:- Objective 3 - provision of a general-purpose methodology for model-based performance evaluation of database replication protocols.