DIverse DatabasE ReplicatiOn - Performance Comparison (DIDERO-PC)

这项建议是关于对各种数据库复制协议的试验性评估。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，并且基于不同的数据库管理系统(DBMS)的使用，即设计上的不同。这些DBMS由不同的供应商开发，既可以是商业产品(例如Microsoft SQL Server、Oracle)，也可以是开源产品(例如MySQL、PostgreSQL)。实验评估将使用两种方法：一种是基于模型的方法，另一种是直接在试验台上进行“真实”系统的实验。不同的数据库复制协议有可能提供比基于使用同一供应商的DBMS的传统方法更高的可靠性保证(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，除了达到适当的可靠性水平外，系统设计人员和其他DBMS利益相关者还对替代解决方案提供的性能特征感兴趣。对于许多应用程序来说，性能实际上是选择过程中的主要标准。在数据库复制协议之间进行公平而彻底的性能比较，包括本提案中研究的那些协议，对于系统设计人员在决策哪种协议最适合集成到他们的系统中非常有用。该项目旨在比较基于不同DBMS使用的三种数据库复制协议的性能：我们的DivRep(参考点)、SES和Byzantium。这三种协议可防止非崩溃故障。要实现的特定性能评估有两个主要目标：-目标1-基于在实验试验台上使用“真实”系统的评估，即使用复制协议与真实DBMS的各自实现。-目标2-基于模型的评估，其中每个复制协议以及DBMS资源用合适的模型(在所选择的特定工具中实现)和通过对相应模型的模拟测量的协议性能来表示。DBMS和相关复制协议的性能比较通常仅基于使用(合成)基准的比较，这在大多数情况下并不反映被测系统的运行概况。此外，仅基于与“真实”系统的实验评估的性能比较所能达到的效果也是有限的：人们只能可行地探索有限范围的参数值(例如副本数量、读写操作之间的比率等)。相比之下，基于模型的方法通过以实用的方式提供具有广泛配置参数的评估手段，提供了更大的灵活性。因此，该提案旨在满足以下目标：--目标3--为基于模型的数据库复制协议性能评估提供一种通用方法。

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.