Tag: INDEX

Feed: Planet MySQL; Author: Øystein Grøvlen; As presented at the Percona Live Conference in Austin in May, at Alibaba we are working on adding support for parallel query execution to POLARDB for MySQL. As discussed in the presentation, we observe that parallel range scans on secondary indexes does not scale very well in MySQL. This is old news. Mark Callaghan reported this several years ago, and this does not seem to have changed. In this blog post, I will investigate what effects using a multi-processor machine have on the scalability of parallel index range scans. I will run a variant ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . Rowid filtering is an optimization in MariaDB 10.4. Its target use case is as follows: a table uses ref access on index IDX1 but it also has a fairly restrictive range predicate on another index IDX2. In this case, it is advantageous to: Do an index-only scan on index IDX2 and collect rowids of index records into a data structure that allows filtering (let's call it $FILTER). When doing ref access on IDX1, check $FILTER before reading the full record Example Consider a query SELECT ... FROM orders JOIN lineitem ON o_orderkey=l_orderkey ... Read More

Feed: R-bloggers. Author: R Views. [This article was first published on R Views, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your content on R-bloggers? click here if you have a blog, or here if you don't. Florianne Verkroost is a PhD candidate at Nuffield College at the University of Oxford. With a passion for data science and a background in mathematics and econometrics. She applies her interdisciplinary knowledge to computationally address societal problems of inequality. In this post, I will show you how to create interactive world maps ... Read More

Feed: Planet PostgreSQL. The transactional model has been in PostgreSQL since the early versions. PostgreSQL implementation follows the guidelines of the SQL standard some notable exceptions. When designing an application it’s important to understand how the concurrent access to data happens in order to avoid unexpected results or errors. The MVCC PostgreSQL implements atomicity, consistency and isolation with the MVCC. The acronym stands for Multi Version Concurrency Control which allows high efficiency in concurrent user access with minimal lock requirements. Depending from the isolation level, when a query or a transaction access the database for the first time acquires a ... Read More

Feed: AWS Compute Blog. Author: Neelay Thaker. This post is contributed by Jeff Underhill | EC2 Principal Business Development ManagerAmazon Corretto is a no-cost, multiplatform, production-ready distribution of the Open Java Development Kit (OpenJDK). Production-ready Linux builds of JDK8 and JDK 11 for the 64-bit Arm architecture were released Sep 17, 2019. Scale-out Java applications can get significant cost savings using the Arm-based Amazon EC2 A1 instances. Read on to learn more about Amazon EC2 A1 instances, Amazon Corretto, and how support for 64-bit Arm in Amazon Corretto is a significant development for Java developers building cloud native applications. What ... Read More

Feed: Planet PostgreSQL. While managing a small team of development resources working on PostgreSQL development, I sometimes get resources in my team that have good development experience but are new to PostgreSQL. I have developed a short set of training instructions in order to get these resources started with PostgreSQL and get them to familiarise themselves with Postgres and its internals. The purpose of this blog is to share these instructions so it can benefit others in a similar situation. The instructions involve going through a lot of documentation, white-papers, online books, it also includes few development exercises that can ... Read More

Feed: AWS Partner Network (APN) Blog. Author: AWS Admin. By Amit Khanal, Solutions Architect at CloudinaryOver the last decade, the number of photos our society has taken and stored is absolutely mind-blowing. Estimates suggest that more than 1 trillion photos were taken in 2018. The shift to digital photography, combined with the availability of smartphone cameras, has made it easy for photographers of all skill levels to take and upload an enormous amount of content every year. These massive image collections can be difficult to manage and organize, let alone a brand that’s trying to manage and deliver tens of ... Read More

Feed: Planet MySQL; Author: Mark Callaghan; The Learned Indexes paper opened a new area of research for storage engines. The idea is to use the distribution of the data to make searches faster and/or reduce the size of search structures. Whether ML will be used is an implementation artifact to me. I am in this for the efficiency gains -- reducing space and CPU read amplification. I prefer to call this topic learned search structures rather than learned indexes because the public isn't ready for learned recovery and learned consistency.While the Learned Indexes paper has ideas for hash maps and bloom filters ... Read More

Feed: Planet big data. Author: Valeryia Shchutskaya. 7 October 2019Author Valeryia Shchutskaya and Katrine SpirinaWhether you are responsible for customer experience, online strategy, mobile strategy, marketing, or any other customer-impacting part of an organization, you’re already aware of some of the ways recommendation technology is used to personalize content and offers.Based on this technology, machine learning (ML) engineers build recommender systems that redefine the ways customers search for products or services, learn about new opportunities and goods they may be interested in. The driving force behind these systems is big data. There are several types of recommender systems, but all of ... Read More

Feed: Featured Blog Posts - Data Science Central. Author: Bill Schmarzo. “It is hard to teach an old dog new tricks.  They’ve only been in business for 155 years.” – Anonymous The Pullman Co (1867), Allied Corp (1920), Heinz (1869), Hughes Tool (1908), Ford Aerospace (1956), Motorola (1928), Bethlehem Steel (1857), Ralston Purina (1894), Compaq (1982), E.F. Hutton (1904), PaineWebber (1880), MCI (1983), Eastern Airlines (1926) and Pan Am Airlines (1927), Houston Natural Gas / Enron (1940), Arthur Andersen (1913), Woolworth's (1879), Standard Oil (1870), General Foods (1895), Kraft (1923)…. A recent article by Peter Bendor-Samuel highlighted 3 reasons why an organization’s ... Read More