Construction and application of Redis cluster

1. Select two servers and install the redis WGet http://download.redis.io/releases/redis-2.8.12.tar.gz tar -xvf redis-2.8.12.tar.gz CD redis-2.8.12 make3, configuration VI redis.conf amending the main daemonize yes bind 192.
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ORC hive file storage format

ORC file format, its full name is Optimized Row Columnar (ORC) file format. Using ORC file format to enhance the performance of Hive read, write and process data. Storage for the data row by row block, each according to the column store compression fast column access efficiency is higher than that of the rcfile is rcfile improved versions of the specific reference to the official website: https://cwiki.apache.org/co...
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R language drawing

Installation venneuler install.packages package (venneuler choice's mirror # load venneuler library package venneuler VD < - venneuler (C (A=0.3, B=0.3, C=1.1, B = 0.1, a & C = 0.2, B & C = 0.1, A&B&C = 0.1)) Plot (VD) # same as C (A=1, `A&B&C`...
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Data structure of R language

Such as access array in the two elements x B x[2] have r many object type for storing data, including scalars, vectors, matrices, arrays, data frame and list 1 scalar scalar is containing only one element of the vector, such as A2 vectors in R vector can understand for a one-dimensional array, each element of the mode must be the same. Function C is the combination function can be created with array. There is no subscript, from 1 to calculate the distance x[c (2:4) access array in the two to four elements x[c (2,4) access array in the second and the four elements 3 matrix...
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Introduction to R language

Statistical R language...
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Image processing tool ImageMagick

ImageMagick is a free creation, editing, synthesis of pictures of the software. It can read, convert, write a variety of formats. Picture cut, color replacement, application of various effects, image rotation, composition, text, line, polygon, ellipse, curve, additional to the picture extension rotation official website described http://www.imagemagick.org/script/index.php ImageMagick & reg; is a the software suite to create...
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MYSQL host to prepare copy structure and switch

1 choose two servers, respectively as primary and standby databases 2 log on to the server, yum install MySQL; Yum install mysql-server; grant replication slave, replication client on *. * repl@'192.168.119.%'identified by' 12...
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JAVA matrix package JAMA learning

JAMA is a basic linear algebra java package, it provides a number of non sparse matrix classes, the programmer can be constructed to manipulate these classes. For regular use to the matrix operation of the code, even if not proficient in linear algebra does not matter, because the JAMA package provides the function has enough, convenient, easy to use, and easy to understand. Summary Jama.Matrix operation constructor set method set (int i JAMA, the function, i...
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Hive use notes

Alter table table1 drop partition day='2015-07-14'; alter table table1 add columns (vist int); lang.reflect ("java.net.URLDecoder" and "decode", URL, "UTF-8") case when B.user_account account is null then 0 else b.us...
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Python two useful library tools Tornado and Fabric

Tornado is FriendFeed using scalable non blocking web server and related tools of the source version. Http://www.tornadoweb.cn/Fabric is a Python library, you can batch tasks in multiple host by SSH. You can write a task script, and then you can use SSH to automatically run on a large number of remote servers by Fabric. These features are well suited for automated deployment of applications, or the implementation of system management tasks. Http://www...
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High performance load balancing cache Web Architecture

High performance web architecture, static and dynamic separation, static cache. Using LVS to achieve 4 load balancing, the use of LVS to achieve HA KeepAlived and other services HA, the use of Nginx to achieve 7 load balance, the use of caching to achieve proxy Squid. Nginx and squid as a service, can be embedded in the front LVS and keepalived. This is a nested structure, as long as your server is sufficient, the business also has the necessary. High performance web architecture, high performance cache, squid cache static resources not only can...
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System throughput, TPS (QPS), user concurrency, performance testing concepts and formulas

System swallow measure elements: swallow a system measure is closely related to (pressure) and request to the CPU consumption, external interface, IO, and so on. The higher the reqeust consumption of a single CPU, the slower the external system interface and the IO effect, the lower the system throughput capacity, the higher the. Several important parameters of the system throughput: QPS (TPS), the number of concurrent, response time QPS (TPS): every second request/ transaction number concurrent number: system while dealing with the affairs of the request/...
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Polygon range point decision algorithm

Judge a two-dimensional coordinate point whether in a polygon box, first of all given range box of each vertex coordinates (in a clockwise direction is given), respectively, into two arrays to compare size range so as to judge the point is in a polygon return box code are as follows: public class RangePoint { X_points double[]; Y_points double[]; Public (RangePoint) {} RangePoint public (doub...
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Weighted random algorithm

A simple according to the right again a realization of a random, weight for several random objects (classification) of hit ratio, weight setting more prone to high life in Vietnam, and can not equal to 100; simple realization of the code are as follows: the import java.util. Java.util.List import; Java.util.Random import; Class WeightRandom public { List categorys static =...
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Linux inter process communication - the use of shared memory

The following will explain the process of inter process communication, another way to use shared memory. One, what is shared memory just as its name implies, shared memory is to allow the process of two unrelated to access the same logical memory. Shared memory is a very effective way to share and transfer data between two running processes. The shared memory between different processes is usually arranged for the same segment of physical memory. Processes can connect the same segment of shared memory to their own address space, and all processes can access the address in the shared memory, as if they were allocated by the C language function malloc. And if a certain...
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