From Counting Words to Counting Lines with Hadoop
What is Hadoop? There are several ways to answer this question when somebody new to the Big Data space throws it at you. Some folks with a delightful sense of humor might answer it this way: “Hadoop is...
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HPE Apollo 4530 Review
Hewlett Packard Enterprise’s (HPE) Apollo is a family of role-based converged-infrastructure compute and storage solutions at the high performance, high-density end of the enterprise performance...
View ArticleAdventures in Performance Debugging
As we’ve built CockroachDB, correctness has been our primary concern. But as we’ve drawn closer to our beta launch, we’ve had to start paying significantly more attention to performance. The design of...
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PouchDB Data Modeling For My Dig Deep Fitness Offline First Mobile Application
CAUTION: I am just a CouchDB / PouchDB novice trying to think-out-loud about data modeling with this particular NoSQL database. I am in no way expert and all remarks made below should be taken with...
View Article排查redisson中订阅connection无故消失的问题
最近在项目中使用了redis结合spring cache一起作了一个缓存，并使用了订阅功能来达到进程间的数据同步。但在测试使用过程中，发现第二天一来，本来应该工作的订阅同步并不能进行。当时没在意，简单重启了事。但后来发现，每天早上相应的同步都不能进行，并且经测试。每个进程的同步都不进行，感觉是redis的订阅出问题了。 1. 验证问题...
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DBA Myths: You can only restore one differential backup
Ok, I know I’m hosting T-SQL Tuesday this month but I still had post I wanted to share. The basic steps when restoring backups are Full Recovery The most recent full backup. The most recent...
View ArticleUnderstanding the Evolution from Relationship Databases to Semantic Graph...
In the ever-changing world of computing and data analytics, organizations are increasingly overcoming the technological constraints that come with the “data age” by transitioning from relational...
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Webinar Wednesday 12/14: MongoDB System Tuning Best Practices
Please join Percona Senior Technical Operations Architect Tim Vaillancourt on Wednesday December 14, at 10:00 am PST/ 1:00pm EST (UTC-8) as he presents MongoDB System Tuning Best Practices . People...
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Trying Amazon API Gateway, Lambda and DynamoDb
At the beginning of September, I visited a JavaDay conference in Lviv, where I listen to a talk about serverless architecture. Today I'd like to try serverless. According to Martin Fowler , serverless...
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Introducing Change Feed support in Azure DocumentDB
We’re excited to announce the availability ofChange Feed support in Azure DocumentDB! With Change Feed support, DocumentDB provides a sorted list of documents within a DocumentDB collection in the...
View ArticleLog Buffer #497: A Carnival of the Vanities for DBAs
In this week’s edition, Log Buffer brings some of the nifty blog posts fromOracle, SQL Server andmysql. Oracle: SQL *PLus on Mac Cloud Data Warehousing for Dummies When 2 Queries Are Better Than 1 Why...
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DynamoDB cannot store empty strings
Re: An AttributeValue may not contain an empty string Posted by: DavidY@AWS Posted on:Mar 30, 2012 7:10 PM in response to:chook_rl Reply Helpful AttributeValues and attribute names may not contain...
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node-mongodb-native原生驱动在固定集合上的坑
我们都知道， mongodb的固定集合，一旦插入数据后，再进行修改数据，会有限制：文档的大小不能改变，只能按照原来文档的大小进行修改。 我在实际项目中，遇到这么一个问题，找了好久才找到问题根源。 整型值无法更新 有一个固定集合的文档，其中有一个status字段，用于标记状态： 使用mongo shell插入了一条记录用于测试： {status:0}...
View ArticleRedis开启远程访问
Redis默认只允许本地访问，要使Redis可以远程访问可以修改redis.conf 打开redis.conf文件在 NETWORK 部分有说明 ################################## NETWORK ##################################### # By default, if no "bind" configuration...
View ArticleMongoDB 3.2.9 请求 hang 分析及 wiredtiger 调优
MongoDB 3.2.9 版本在 wiredtiger 上做了很多改进，但不幸的时，这个版本引入了一个新的 bug，持续大量 insert/update 场景，有一定的可能导致 wiredtiger 进入 deadlock ，MongoDB 官方迅速的在 3.2.10 里修复了该问题，该版本在 wiredtiger 内存使用上也做了控制，尽量避免了 因为内存碎片导致 wiredtiger...
View ArticleSpring Data Redis 使用redis的一些方法点
在applicationContext,xml中设置 spring 的redis的使用配置信息 <!--jedis的连接池配置 --> <bean id="poolConfig" class="redis.clients.jedis.JedisPoolConfig"> <!-- 最大空闲连接数量 --> <property name="maxIdle"...
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聊一聊分布式锁的设计 （redis 分布式锁）
http://weizijun.cn/2016/03/17/%E8%81%8A%E4%B8%80%E8%81%8A%E5%88%86%E5%B8%83%E5%BC%8F%E9%94%81%E7%9A%84%E8%AE%BE%E8%AE%A1/ 起因 前段时间，看到redis作者发布的一篇文章 《Is Redlock safe?》...
View Articleissue #47: OpenSSL, ripgrep, httpstat, CouchDB, Latency & more!
Welcome to cron.weekly issue #47 for Sunday, September 25th, 2016. A bit later than usual, but I’m liking it better this way. From now on, cron.weekly is not going to have a fixed time for delivery....
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Ambari Metrics 详解
Ambari 作为一个出色的集群管理软件，为第三方服务提供了丰富的功能。其中 Ambari Metrics System 为第三方服务以及集群机器提供了性能相关的监察功能。本文主要讲解 Ambari Metrics 框架的原理，以及如何集成该系统与第三方服务。 Ambari 现状 Ambari 最新的发行版已经到了 2.2.1 的版本，提供了更多的管理功能，例如在 2.2 的版本中支持了...
View ArticleRedis持久化
本章节我们来看看Redis时如何就爱那个数据存储到硬盘里面，是的数据在Redis重启之后仍然存在的。Redis提供了两种不同的持久化方法来将数据存储到硬盘里面。一种方法叫快照(snapshotting)，它可以将存在于某一时刻的所有数据都写入硬盘里；另一种方法教只追加文件(append-only file,...
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