When NoSQL database systems are used in an agile software development setting, data model changes occur frequently and thus, data is routinely stored in different versions. The management of versioned data leads to an overhead potentially impeding the software development. Several data migration strategies exist that handle legacy data differently during data accesses, each of which can be characterized by certain advantages and disadvantages. Depending on the requirements for the software application, we evaluate and compare different migration strategies through metrics like migration costs and latency as well as precision and recall. Ideally, exactly that strategy should be selected whose characteristics fulfill service-level agreements and match the migration scenario, which depends on the query workload and the changes in the data model which imply an evolution of the database schema. In this paper, we present a methodology of self-adapting data migration, which automatically adjusts migration strategies and their parameters with respect to the migration scenario and service-level agreements, thereby contributing to the self-management of database systems and supporting agile development.

在敏捷软件开发设置中使用NoSQL数据库系统时，数据模型更改频繁发生，因此，数据通常存储在不同版本中。版本化数据的管理会导致潜在的开销，从而可能阻碍软件开发。存在几种数据迁移策略，这些策略在数据访问期间以不同方式处理旧数据，每种策略都有某些优点和缺点。根据软件应用程序的要求，我们通过诸如迁移成本和延迟以及精度和召回率等指标评估和比较不同的迁移策略。理想情况下，应该准确地选择其特征满足服务水平协议并与迁移方案相匹配的策略，这取决于查询工作负载和数据模型的变化，这暗示着数据库模式的发展。在本文中，我们提出了一种自适应数据迁移的方法，该方法可以根据迁移方案和服务级别协议自动调整迁移策略及其参数，从而有助于数据库系统的自我管理并支持敏捷开发。