Tag: column

Feed: AWS Partner Network (APN) Blog. Author: Jignesh Desai. By Karthik Mohan and Rajeev Rangachari, Senior Architects at InfosysBy Jignesh Desai, Partner Solutions Architect at AWSIn an era where always-on connectivity, the Internet of Things (IoT), and unstructured data in the public domain are the new normal, the ability of companies to compete and differentiate rests on their ability to leverage data and analytics. Winning companies take advantage of the wealth of information available to create valuable insights and act on them. We call these organizations analytics-driven enterprises, and they use actionable insights to deliver on the promise of data ... Read More

Feed: R-bloggers. Author: Biswarup Ghosh. In the exercises below, we will work with FFTree pacakge which lets us use fast and frugal decision tree to model the data Please install the package and load the library before startingAnswers to these exercises are available here. If you obtained a different (correct) answer than those listed on the solutions page, please feel free to post your answer as a comment on that page. Exercise 1 FFTree package comes with heart.train,heart.test data .Check the heart.train data and see the diagnosis column .This is our response variable .Create a FFTree model using heart.test,heart.train and ... Read More

Feed: Planet MySQL; Author: Dave Stokes; There was an interesting question on Stackoverflow.com on extracting values from a JSON data type column in a MySQL database.  What caught my eye was the the keys for the key/value pairs were numeric. In particular the author of the question only wanted values for the key named 74.  The sample data was fairly simple.{ "70" : "Apple", "71" : "Peach", "74" : "Kiwi" }I thought SELECT JSON_EXTRACT(column, '$.74') FROM table; should work but it did not. There was a complaint about an invalid path expression.It turns out that you need to make the ... Read More

Feed: Planet PostgreSQL. We spend a lot of time with companies that are growing fast, or planning for future growth. It may be you’ve built your product and are now just trying to keep the system growing and scaling to handle new users and revenue. Or you may be still building the product, but know that and even moderate level of success could lead to a lot of scaling. In either case where you spend your time is key in order to not lose valuable time. As Donald Knuth states it in Computer Programming as an Art: “Programmers waste enormous ... Read More

Feed: Planet MySQL; Author: MySQL Server Dev Team; In this article, I’ll explain about the multi version concurrency control (MVCC) of large objects (LOBs) design in the MySQL InnoDB storage engine.  MySQL 8.0 has a new feature that allows users to partially update large objects, including the JSON documents.  With this partial update  feature the way MVCC works for LOBs has changed when there are partial updates to LOBs.  For normal updates (the full update), MVCC will work as it did in previous versions. Lets look at  how MVCC works when partial update is not involved, and then consider the use ... Read More

Feed: R-bloggers. Author: . How Has Taylor Swift’s Word Choice Changed Over Time?Sunday night was a big night for Taylor Swift – not only was she nominated for multiple Billboard Music Awards; she took home Top Female Artist and Top Selling Album. So I thought it was a good time for some more Taylor Swift-themed statistical analysis. When I started this blog back in 2011, my goal was to write deep thoughts on trivial topics – specifically, to overthink and overanalyze pop culture and related topics that appear fluffy until you really dig into them. Recently, I’ve been blogging more ... Read More

Feed: Planet PostgreSQL. Working with databases, concurrency control is the concept that ensures that database transactions are performed concurrently without violating data integrity. There is a lot of theory and different approaches around this concept and how to accomplish it, but we will briefly refer to the way that PostgreSQL and MySQL (when using InnoDB) handle it, and a common problem that can arise in highly concurrent systems: deadlocks. These engines implement concurrency control by using a method called MVCC (Multiversion Concurrency Control). In this method, when an item is being updated, the changes will not overwrite the original data, ... Read More

Feed: MemSQL Blog. Author: Eric Boutin. On March 13, we published a blog demonstrating the performance of MemSQL in the context of ad hoc analytical queries. Specifically, we showed that the query SELECT stock_symbol, count(*) as c FROM trade GROUP BY stock_symbol ORDER BY c desc LIMIT 10; SELECT stock_symbol, count(*) as cFROM tradeGROUP BY stock_symbolORDER BY c descLIMIT 10; can process 1,280,625,752,550 rows per seconds on a MemSQL cluster containing 448 Intel Skylake cores clocked at 2.5GHz. In this blog post, we drill down into how this was made possible by carefully designing code, exploiting distributed execution, and instruction-level ... Read More

Feed: R-bloggers. Author: Qitao Chen. Problem Image that someone in a bank want to find out whether some of bank’s credit card holders are acctually the same person, so according to his experience， he set a rule: the people share either the same address or the same phone number can be reasonably regarded as the same person. Just as the example: library(tidyverse) a In the dataframe ]czoxOlwiYVwiO3tbJiomXX0=[ , the letters in column ]czo0OlwiYWRkclwiO3tbJiomXX0=[ stand for address information, the numbers in column ]czo1OlwicGhvbmVcIjt7WyYqJl19[ stand for phone numbers, and the integers in column ]czo0OlwiZmxhZ1wiO3tbJiomXX0=[ is what he want: the CLUSTER flag which ... Read More

Feed: R-bloggers. Author: John Mount. wrapr 1.4.1 is now available on CRAN. wrapr is a really neat R package both organizing, meta-programming, and debugging R code. This update generalizes the dot-pipe feature’s dot S3 features. Please give it a try! wrapr, is an R package that supplies powerful tools for writing and debugging R code. Introduction Primary wrapr services include: let() (let block) %.>% (dot arrow pipe) build_frame()/draw_frame() := (named map builder) DebugFnW() (function debug wrappers) λ() (anonymous function builder) let() allows execution of arbitrary code with substituted variable names (note this is subtly different than binding values for names ... Read More