UDP is a good choice in situations where delayed data is worthless. For example, in a VoIP phone call, there probably isn’t enough time to retransmit a lost packet before its data is due to be played over the loudspeakers. In this case, there’s no point in retransmitting the packet—the application must instead fill the missing packet’s time slot with silence (causing a brief interruption in the second) and move on in the stream. The retry happens at the human layer instead. (“Could you repeat that please? The sound just cut out for a moment.”) (查看原文)
For data warehouse queries that need to scan over millions of rows, a big bottleneck is the bandwidth for getting data from disk into memory. However, that is not the only bottleneck. Developers of analytical databases also worry about efficiently using the bandwidth from main memory into the CPU cache, avoiding branch mispredictions and bubbles in the CPU instruction processing pipeline, and making use of single-instruction-multi-data (SIMD) instructions in modern CPUs.
Besides reducing the volume of data that needs to be loaded from disk, columnoriented storage layouts are also good for making efficient use of CPU cycles. For example, the query engine can take a chunk of compressed column data that fits comfortably in the CPU’s L1 cache and iterate through it in a tight loop (that is, w... (查看原文)
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1 有用 无耻之徒 2018-11-11 00:13:08
很体系化的一本技术书籍，后面的论文可深入研究，五星不准掉，略微比预期差些。
0 有用 acAric 2022-02-21 21:52:43
简明扼要的讲述目前分布式以及高可用等相关设计基于的设计，推荐一看。
0 有用 浮舟 2019-09-02 07:10:13
为了复习看的，有种高屋建瓴的感觉！
1 有用 Wuyouz 2018-06-23 18:28:52
梳理全面，见解独到
1 有用 will 2022-06-11 22:39:31
这本书以俯瞰的角度来分析现在的应用(data-intensive数据密集)。我收获很大的部分有database storage，replication，partitioning，transactions，batch processing and stream processing。一个月每天阅读一个半小时啃下来，吸收率大概在60%。接下来吸收一段时间之后根据现实遇到的问题再回过头来复习。