1. Given a, b two files, each store 5 billion URLs, each URL accounted for 64 bytes, memory limit is 4G, let you find a, b file common URL? Scenario 1: The size of each file can be estimated to be 50gx64=320g, far larger than the memory limit of 4G. So it is not possible to fully load it into memory processing. Consider adopting a divide-and-conquer approach. s traverses file A, asks for each URL, and then stores the URL to 1000 small files (recorded) based on the values obtained. This ...
In addition to the "normal" file, HDFs introduces a number of specific file types (such as Sequencefile, Mapfile, Setfile, Arrayfile, and bloommapfile) that provide richer functionality and typically simplify data processing. Sequencefile provides a persistent data structure for binary key/value pairs. Here, the different instances of the key and value must represent the same Java class, but the size can be different. Similar to other Hadoop files, Sequencefil ...
The sorting algorithm can be divided into internal sorting and external sorting. The internal sorting is to sort the data records in the memory, while the external sorting is because the sorting data is very large, so it can not hold all the sorting records at a time. In the sorting process, it needs to access the external memory. Common internal sorting algorithms are: Insert sort, Hill sort, Select sort, Bubble sort, Merge sort, Quick sort, Heap sort, Base sort and so on. This article will introduce the above eight sorting algorithm in turn. Algorithm 1: insert sort Insert sort diagram Insert sort is one of the most simple and intuitive sorting algorithm, it's work ...
About the Internet of things (Internet of Things, abbreviated IoT) is an internet-based, traditional telecommunications network, such as information carrier, so that all can be independently addressed common physical objects to achieve interconnection network. The internet of Things is generally wireless network, since everyone around the equipment can reach 1000 to 5,000, so the Internet may have to contain 500 trillion to 1000 trillion objects, in the Internet of things, everyone can use electronic tags to connect real objects online, can find out their specific location on the Internet of things. Pass STH.
Despite the advent of professional tools such as Google Apps, self-contained devices (BYOD) Policies and Dropbox, the more data, applications, and accesses are in the cloud, the reliable Virtual private network (VPN) strives to keep the WAN abreast. James Gordon is vice president of information technology at Needham Bank, who, like many IT managers, does not trust the latest cloud products, such as Microsoft and Google products. In his extremely stringent financial institutions, "not my server" does not mean "not my problem." ” ...
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