spark definitive guide

ArticleDirectory Efficiency Transmission Performance Today, I downloaded an electronic version of MongoDB the definitive guide and browsed the content in it, which is quite rich. Is a supplement to the practical application of the official website documentation. Similar to the official document, the internal principles of MongoDB are rarely described. Only the relevant content is descr

; Db.users.update ({"name": "Joe"}, Joe) Using the modifier $set, $inc, $ne, $push, $addToSet, $each //Add or remove a key valueDb.users.update ({"Name": "Joe"}, {"$set": {"Favorite book": "War and Peace"}}) db.users.update ({"Name": "Joe"}, {"$unset": {"Favorite book": 1}}) //Increase or decrease valueDb.games.update ({"Game": "Pinball", "User": "Joe"}, {"$inc": {"score": 50}}) //add a value to an arrayDb.papers.update ({"Authors cited": {"$ne": "Richie"}}, {"$push": {"authors cited": "Richie

A function is a special object;Object: A collection of properties (name-value pairs);The function is used to initialize (with the new operator) a newly created object is called a constructor.The object is called as a method when the property is a function.Within a function body, a local variable takes precedence over a global variable of the same name.code example:varscope = "global"; // Declare a global variablefunctionCheckscope () {varScope = "local";//life a local variable with the same nam

(int)$php;//output results: 0?>//other types are converted to String typePHP$php=100.1; Var_dump((string)$php);//Output: String (4) "100.1" $php=true; Echo(string)$php;//output results: 1?>//other types are converted to floating-point typePHP$php= "123.2php"; Var_dump((float)$php);//output Result: float (123.2) $php= "php123.2"; Var_dump((float)$php);//output results: (0)?>//Other types convert to BooleanPHP$php= "PHP"; Var_dump((BOOL)$php);//Output Result: bool (TRUE) $php=0; Var_dump(

Learn the C + + book listTurn fromHttp://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-listBeginnerintroductoryIf you were new to programming or if you had experience in other languages and is new to C + +, these books is highly reco Mmended. C + + Primer * (Stanley Lippman, Josée Lajoie, and Barbara E. Moo) (updated for c++11) Coming at 1k pages, This was a very thorough introducti

Today downloaded the "MongoDB The Definitive Guide" electronic version, browsing the content inside, or quite rich. is a supplement to the actual application of official website documents. Similar to the official documentation, the introduction of MongoDB's internal principles is minimal, and only a section of the appendix describes the relevant content.MongoDB is like a big black box for most mongodb users

techniques to manage very big C + + software projects. Certainly a good read, if it is only is up to date. It was written long before c++98, and misses on many features (e.g. namespaces) important for large scale projects. If you need-to-work in a big C + + software project, you might want to read it, although-need-take-more than a grain of salt with it. The first volume of a new edition is expected in 2015. Inside the C + + Object Model (Stanley Lippman) If you want to know how virtual membe

After Oracle acquired Stellent, it packaged the original Stellent Content Management system into Oracle Universal Content Management. However, most of the UCM product documentation and vendor training courses are about how to use the system. This Definitive Guide to Stellent Content Server Development is still required for deep-seated issues such as how to develop components. This book is at least fully usa

the style and logic of the above code is no longer familiar: Create a The Schedulerserver object, which passes command-line arguments, and enters the schedulerserver Run method, does not die. --"kubernetes authoritative guide" source code guidance Kubernetes Scheduler Server is implemented by the Kube-scheduler process, which runs on the Kubernetes management node--master and is primarily responsible for completing the pod-to-node scheduling process.K

GetCookie () function that resolves the value of the Document.cookie property, stores the corresponding name/value pair in an object, and returns the object at the end of the function.Parsing Document.cookie Property values/** returns the value of Document.cookie as an object of name/value pairs * Assuming that the value of the stored cookie is encoded with the encodeurlcomponent () function */function GetCookie () { var cookie = {}; Initialize the last object to

A definitive guide to PHP development-reading summary

PDF version, English version 158th page,var IsArray = Function.isarray | | Function (o) {return typeof o = = = = "Object" object.prototype.tostring.call (o) = = = "[Object Array]";}; return typeof o = = = "Object" object.prototype.tostring.call (o) = = = "[Object Array]";};Array.isarray is a function provided by ES5, this example is to implement this function in ES3, first, if the browser supports Array.isarray, it is assigned to IsArray, otherwise the subsequent function is assigned to IsArray.

either by the drivers or By a user ' s application code). Maintaining this streamlined (streamlined; improved) design is one of the reasons MongoDB can achieve such high performance.Simple administrationMongoDB tries to simplify database administration by making servers administrate themselves as much as possible. Aside from starting the database server, very little administration is necessary. If a master server goes down, MongoDB can automatically failover (fail-over redundancy) to a backup s

: The instance method of JS must use the This keyword, and the class's methods usually do not use the This keyword, they refer to its parameter operation;The P222-based inheritance mechanism in the extended p223js of class 9.4 is dynamic: Objects inherit properties from other prototypes, and if the properties of the prototype change after the object is created, it also affects all instance objects that inherit the prototype, and we can augment the JS class by adding a new method to the prototype

be adjusted to improve the performance of the job immediately. We need to perform a comprehensive analysis of the spark job based on different business scenarios and data conditions, and then adjust and optimize it in many ways to get the best performance.Based on the previous experience of spark job development and the accumulation of practice, the author summarizes a set of performance optimization schem

This article from the official blog, slightly added: https://github.com/mesos/spark/wiki/Spark-Programming-GuideSpark sending Guide From a higher perspective, in fact, every Spark application is a Driver class that allows you to run user-defined main functions and perform various concurrent operations and calculations

drivers. Spark supports two types of shared variables: broadcast variables, which can cache a value in memory for all nodes, an accumulator, a variable that can only be added, such as counters and sums.This guide shows each of the features of spark in each of the languages supported by Spark. It's easiest to follow al

yarn-cluster --class Iteblog. Kafkatest 　　　　--jars lib/spark-streaming-kafka_2.10-1.3.0. Jar, Lib/spark-streaming_2.10-1.3.0. Jar, Lib/kafka_2.10-0.8.1.1.jar,lib/zkclient-0.3. Jar, Lib/metrics-core-2.2.0.jar./ Iteblog-1.0-snapshot.jarThe following is a complete example:Object Kafkawordcount {def main (args:array[string]) {if(Args.length ) {System.err.println ("Usage:kafkawordcount ) System.exit (1)} stre

in the following three areas: (1) Spark Rdd can be converted to Schemardd by reflection inference schema or encoding specified schema, and Schemardd is created as "datasheet", Allows us to analyze the data in the form of SQL statements, saving a lot of coding effort; (2) Spark SQL allows us to dynamically create custom SQL functions on demand while the application is running, expanding the data processing

use a lambda expression to complete the definition function with the registration process, as in the example above. Our custom SQL functions can be used in conjunction with Hive UDFs, as shown in the following example: where Func.iptolocationbysina is a hive udf (Permanent Function). Mychange is a custom SQL function. As you can see from the two examples above, custom SQL functions are far more flexible than hive UDFs. The creation of Hive UDFs is complex and requires the use of the Java lang