The concept of unstructured Peer-to-Peer (P2P) systems—setting free from any structural constraints—has put forward an appropriate paradigm for sharing a wide assortment of resources in a distributed-sharing manner efficiently. More importantly, unstructured P2P systems’ architecture and concepts have permeated diverse spheres of today’s successful and world-famous computer science areas, including NoSQL databases for excellently sharing data. However, pinpointing any given appropriate resource in such massive systems, namely unstructured P2P systems, is a challenging task; the two of the most dispensable rationales behind this proclaim are large scales of such systems and unstructured nature of overlay networks. Finding a decent resource with low response time, low bandwidth consumption, and high success-rate has played a crucial role in both the overall system performance and the functionality of P2P systems. Briefly, an efficacious resource discovery mechanism is the lifeblood of any productive P2P system. Given these points, in this study, we present an exhaustive survey on state-of-the-art resource discovery mechanisms employed in file-sharing pure unstructured P2P systems; we offer a new resource discovery categorization accordingly. Furthermore, we deeply delve into a plethora of resource searching methods and their merits as well as demerits to furnish the paper with an in-depth evaluation.

不受任何结构性约束的非结构化对等（P2P）系统的概念提出了一种合适的范例，可以有效地以分布式共享的方式共享各种资源。更重要的是，非结构化的P2P系统的体系结构和概念已渗透到当今成功和举世闻名的计算机科学领域的各个领域，包括NoSQL数据库，以实现出色的数据共享。然而，在这样的大型系统中，即非结构化的P2P系统中，找到任何适当的资源是一项艰巨的任务；此声明背后的两个最不可或缺的理由是此类系统的规模庞大以及覆盖网络的非结构化性质。寻找响应时间短，带宽消耗低，高成功率在P2P系统的整体系统性能和功能方面都起着至关重要的作用。简而言之，有效的资源发现机制是任何生产性P2P系统的命脉。考虑到这些要点，在本研究中，我们将对文件共享纯非结构化P2P系统中使用的最新资源发现机制进行详尽的调查。我们相应地提供了一种新的资源发现分类。此外，我们深入研究了多种资源搜索方法及其优点和缺点，以便为本文提供深入的评估。我们对文件共享纯非结构化P2P系统中采用的最新资源发现机制进行了详尽的调查；我们相应地提供了一种新的资源发现分类。此外，我们深入研究了多种资源搜索方法及其优点和缺点，以便为本文提供深入的评估。我们对文件共享纯非结构化P2P系统中采用的最新资源发现机制进行了详尽的调查；我们相应地提供了一种新的资源发现分类。此外，我们深入研究了多种资源搜索方法及其优点和缺点，以便为本文提供深入的评估。