Indexes are special purpose data structures, designed to facilitate and speed up the access to the contents of a file. Indexing has been actively and extensively investigated in DBMSes equipped with hard disk drives (HDDs). In the recent years, solid-state drives (SSDs), based on NAND flash technology, started replacing magnetic disks due to their appealing characteristics: high throughput/low latency, shock resistance, absence of mechanical parts, low power consumption. However, treating SSDs as simply another category of block devices ignores their idiosyncrasies, like erase-before-write, wear-out and asymmetric read/write, and may lead to poor performance. These peculiarities of SSDs dictate the refactoring or even the reinvention of the indexing techniques that have been designed primarily for HDDs. In this work, we present a concise overview of the SSD technology and the challenges it poses. We broadly survey 62 flash-aware indexes for various data types, analyze the main techniques they employ, and comment on their main advantages and disadvantages, aiming to provide a systematic and valuable resource for researchers working on algorithm design and index development for SSDs. Additionally, we discuss future trends and new lines of research related to this field.

中文翻译：

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闪存设备的索引编制：有关挑战，当前方法和未来趋势的调查

索引是特殊用途的数据结构，旨在促进和加快对文件内容的访问。索引已在配备硬盘驱动器（HDD）的DBMS中进行了积极而广泛的研究。近年来，基于NAND闪存技术的固态驱动器（SSD）由于其吸引人的特性而开始取代磁盘：高吞吐量/低延迟，抗冲击，没有机械部件，低功耗。但是，将SSD仅仅视为另一类块设备会忽略它们的特质，例如写前擦除，磨损和不对称读/写，可能会导致性能下降。SSD的这些特性决定了重构或什至是重新发明了主要为HDD设计的索引技术。在这项工作中 我们简要介绍了SSD技术及其带来的挑战。我们广泛调查了62种针对各种数据类型的闪存感知索引，分析了它们使用的主要技术，并对它们的主要优点和缺点进行了评论，旨在为从事SSD的算法设计和索引开发的研究人员提供系统和宝贵的资源。此外，我们讨论了与该领域相关的未来趋势和新的研究领域。