djangoredismemcached安装和配置 djangoredismemcached安装 djangoredismemcached配置
毕业设计可能不能过关了，所以努力找各种提高服务器性能的方案。前不久听到闺蜜钟钟说过memcached缓存数据库，这几天做了相关调研，记录如下：数据库Redis, Memcache, mongoDB的区别：...
View Articleleftjoin(左联接)rightjoin(右联接)innerjoin(等值连接)区别 左联接 右联接 等值连接 ...
left join(左联接) 返回包括左表中的所有记录和右表中联结字段相等的记录right join(右联接) 返回包括右表中的所有记录和左表中联结字段相等的记录inner join(等值连接) 只返回两个表中联结字段相等的行举例如下：--------------------------------------------表A记录如下：aID aNum1 a200501112...
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Hadoop: The Definitive Guide Exclusive Book Review
Hadoop is the number one big data analysis platform. This book is one of the best available hadoop books and deserves to be a bookshelf of every hadoop developer. We have exclusive review of this book...
View ArticleJDBC的事务处理 JDBC事务处理 JDBC教程 JDBC基本知识
JDBC的事务基本知识 事务的定义：一个事务是由一条或多条对数据库操作的sql语句所组成的一个不可分割的工作单元，只有当事务中的所有操作都正常执行后，整个事务才会提交给数据库。 结束事务的操作：commit()/rollback()。commit表示对事务的提交，rollback表示对事务的回滚，这两种方法都处于java.sql.Connection类中。...
View Article使用rowid实现高速分页查询 高速分页查询 rowid教程 rowid实现高速分页查询
oracle在11g版本中针对rowid分页查询进行了优化，相对于使用rownum 大大提高了查询速度 oracle中rowid高速分页解析 --rowid分页，第一步 select rowid rid,sal from emp order by sal desc; --rowid分页，第二步 select rownum rn,rid from(select rowid rid,sal from...
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An Afternoon of Code Golf (in Lua) to Achieve 4x Performance in Redis
Amplitude collects tens of thousands of user events per second. Processing all these events involves a multistep processing pipeline that has dozens of steps and dependencies. We use a variety of...
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Percona Server for MongoDB 3.2.12-3.2 is now available
Percona announces the release of Percona Server for MongoDB 3.2.12-3.2 on March 9, 2017. Downloadthe latest version from thePercona web siteor the Percona Software Repositories . Percona Server for...
View ArticleNoSQL LinkedIn Users Listed with Neo4j Skills
ByAileen Agricola | March 9, 2017 More Than 19,000 LinkedIn Users List Neo4j as a Skill as Professional Neo4j Community Continues to Grow Today Neo Technology, creator of the world’s leading graph...
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深入讲解SQL中的字符串拼接
一、概述相信大家在日常开发中，在SQL语句中经常需要进行字符串拼接，以sqlserver，oracle，mysql三种数据库为例，因为这三种数据库具有代表性。sqlserver：select '123'+'456';oracle：select '123'||'456' from dual;或select concat('123','456') from dual;mysql：select...
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利用reverse索引优化like语句的方法详解
前言在有一些情况下，开发同学经常使用like去实现一些业务需求，当使用like时，我们都知道使用like 前%（like ‘%111'）这种情况是无法使用索引的，那么如何优化此类的SQL呢，下面是一个案例。原SQL如下：pcc_cust_infonew 表索引如下执行设计如下：这里可以看到SQL执行3.96秒，执行计划中也可以发现PCC_CUST_INFONEW表走TABLE ACCESS...
View ArticleSQL注入绕过的技巧总结
前言sql注入在很早很早以前是很常见的一个漏洞。后来随着安全水平的提高，sql注入已经很少能够看到了。但是就在今天，还有很多网站带着sql注入漏洞在运行。稍微有点安全意识的朋友就应该懂得要做一下sql注入过滤。SQL注入的绕过技巧有很多，具体的绕过技巧需要看具体的环境，而且很多的绕过方法需要有一个实际的环境，最好是你在渗透测试的过程中遇到的环境，否则如果仅仅是自己凭空想，那显然是不靠谱的。这篇文章就...
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Neo4j basic visualization (spoon,Zeppelin)
I started using Neo4j about 7 months ago and loved it from the first successful LOAD CSV on. As my skills of cypher and modeling increased, the bigger was the need for visualizing data and drilling...
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Data Lake 3.0 Part 2 A Multi-Colored YARN
Thank you for reading our Data Lake 3.0 series! In part 1 of the series , we briefly introduced the power of leveraging prepackaged applications in Data Lake 3.0 and how the focus will shift from the...
View ArticleBro, do you even Pillow?
Pillow is a fork of the python Imaging Library. Here is an update on the status of the project. 2.4.0 released Pillow 2.4.0 is out! Here are the highlights: Indexed Transparency handled for conversions...
View ArticleService Fabric KeyValueStoreReplica, ReplicaRole
TL;DR After taking a look at how actors’ state is persisted with KeyValueStoreReplica to follothe prefix query guideline, it’s time to see how this state is replicated. ReplicaRole When defining...
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Miles to go ... - Arun Gupta: Start Couchbase Using Docker Compose
Couchbase Forumshas a question Can’t use N1QL ondocker-compose . This blog will show how to run Couchbase using Docker Compose and run a N1QL query . What is Docker Compose? Docker Compose allows you...
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Miles to go ... - Arun Gupta: Stateful Containers using Portworx and Couchbase
Containers are meant to be ephemeral and so scale prettywell for stateless applications. Stateful containers, such as Couchbase, need to be treated differently. Managing Persistence for Docker...
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Miles to go ... - Arun Gupta: NoSQL Simplifies Database DevOps
Does your organization want to simplify Database DevOps? Is your database becoming a bottleneckto innovate rapidly? Do you want to save millions of $$ in database licensing cost? Read on! State of...
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日志与行为数据存储查询剖析
写在前面 近些年，大数据背后的价值也开始得到关注和重视，越来越多的企业开始保存和分析数据，希望从中挖掘大数据的价值。大数据产生的根本还是增量数据，单纯的用户数据不足以构成大数据，然而用户的行为或行为相关的日志的数据量，加之随着物联网的发力，产生的增量数据将不可预估，存储和查询增量数据尤为关键。所以，在笔者的工作经历中，本着以下的目标，寻找更优的大数据存储和查询方案：...
View ArticleMongodb 快速上手
MongoDb 官网 安装环境Centos 6.7 x64 安装 Binary安装 curl -o mongo.tar.gz https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-rhel62-3.4.2.tgz tar -xvzf mongodb-linux-x86_64-rhel62-3.4.2.tgz cd...
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