Dkron - Cloud native job scheduling system | Dkron
Dkron is a system service for workload automation that runs scheduled jobs, just like unix cron service but distributed in several machines in a cluster. This is the only job scheduler in the market with truly no SPOF. It is open source and available for free. Easy integration Dkron is easy to setup and use. Choose your OS package and it's ready to run out-of-the-box. The administration panel and
とても長い配列の上位M件だけをクイックソートより高速に取り出す - Qiita
というわけで、10倍の差がでた。 当然、配列の長さやソートする長さ、また実装の方法によって性能差は変わってくるが 今回の方法は有効であるということは確認できた。 既存の記事(2015/11/09 20:22 追記) コメント欄でUnordered partial sorting にそれらしきことが書いてあると教えていただいた。 そちらでは、「上位k個を取り出す（ソートは不要）」という問題を考えている。 同様に分割統治法を用いてソートしていきながら、上位k個以内の小区間になったらその区間はソートせずに全て選択して良いとしている。 早い話が、QuickSelectによりk+1番目の要素を探してそれより上位の要素をごそっと抜き出している。 分割統治法で大雑把にソートしていきながら、不要なソートを行わないようにする という同様のアプローチである。 C++のSTLの場合(2015/11/09 22:
Tuning TCP and NGINX on EC2
Chartbeat measures and monetizes attention on the web. They were experiencing slow load times and TCP retransmissions due to default system settings. Tuning various TCP, NGINX and EC2 ELB settings like increasing buffers, disabling Nagle's algorithm, and enabling HTTP keep-alive resolved the issues and improved performance. These included tuning settings like net.ipv4.tcp_max_syn_backlog, net.core
(WEB401) Optimizing Your Web Server on AWS | AWS re:Invent 2014
(WEB401) Optimizing Your Web Server on AWS | AWS re:Invent 2014 Tuning your EC2 web server will help you to improve application server throughput and cost-efficiency as well as reduce request latency. In this session we will walk through tactics to identify bottlenecks using tools such as CloudWatch in order to drive the appropriate allocation of EC2 and EBS resources. In addition, we will also be
Diving into HDFS
Yesterday I wanted to start learning about how HDFS (the Hadoop Distributed File System) works internally. I knew that It’s distributed, so one file may be stored across many different machines There’s a namenode, which keeps track of where all the files are stored There are data nodes, which contain the actual file data But I wasn’t quite sure how to get started! I knew how to navigate the filesy
Why you should understand (a little) about TCP
This isn’t about understanding everything about TCP or reading through TCP/IP Illustrated. It’s about how a little bit of TCP knowledge is essential. Here’s why. When I was at the Recurse Center, I wrote a TCP stack in Python (and wrote about what happens if you write a TCP stack in Python). This was a fun learning experience, and I thought that was all. A year later, at work, someone mentioned on
What is the difference in idea, design and code, between Apache Spark and Apache Hadoop?
Answer (1 of 17): When I was getting started with using Apache Spark, I had the same question. From everything I heard, it seemed as if Spark does the same things as Mapreduce but better and faster. But, as it turns out that’s not the case. A few resources (linked below) have helped me with that ...
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How does SQLite work? Part 2: btrees! (or: disk seeks are slow don't do them!)