cassandra

titan-1.0.0-hadoop1 compatibilty issues with apache-cassandra-3.2

由 為{幸葍}努か 提交于 2020-01-06 14:58:37
问题 I am trying to connect titan-1.0.0-hadoop1 with apache-cassandra-3.2 . I am using following " titan-cassandra-myfile.properties ": storage.cassandra-config-dir=titan-1.0.0- hadoop1/conf/cassandra/cassandra.yaml storage.backend=cassandra storage.hostname=localhost When I use gremlin to execute following command: g=TitanFactory.open("/path to titan/ titan-1.0.0-hadoop1/conf/titan-cassandra-myfile.properties"); I am getting following error: java.lang.IllegalArgumentException: Could not

DataStax Opscenter Agent doesn't connect: “Unable to locate cassandra.yaml configuration file”

由 落花浮王杯 提交于 2020-01-06 14:52:11
问题 I have installed Datastax Community Edition v2.0.3 on a Windows Server 2012 R2 Datacenter machine. After a vanilla install, I can't connect to the database with OpsCenter because the agent failed to start: it says "0 of 1 agents connected" in the top of the page. I can connect to the database itself using CQLSH. This problem does not occur with v2.0.2. My datastax_opscenter_agent-stderr.log file contains the following: 2013-12-05 16:16:54 Commons Daemon procrun stderr initialized Exception in

Data Structure in Cassandra

由 允我心安 提交于 2020-01-06 05:48:25
问题 Is there a way to read the SSTable in Cassandra? I see from the documentation that sstabledump is an enterprise version, Is it possible to get the trial version of sstabledump? Or is there a way to read the SSTable using the existing utilities in Cassandra/bin folder? 回答1: sstabledump is also available in apache cassandra. It can be found in tools/bin directory in cassandra 3.x Note: sstable2json was replaced by sstabledump in 3.0 回答2: You can use sstable2json for that. http://docs.datastax

How to enable remote JMX connections in Elassandra?

由 别说谁变了你拦得住时间么 提交于 2020-01-06 04:57:05
问题 I'm trying to enable JMX in Elassandra 5.5.0.4 through cassandra-evn.sh file in order to connect to a Cassandra node, remotely , and get metrics and statistics. I'm trying to connect to JMX using JConsole . I have followed various tutorial from datastax and blogs without success. I tried with and without authentication but nothing worked. 回答1: Make sure the below parameters are set. The configuration enables JMX metrics remotely without any authentication. # add this if you're having trouble

Promise closure within loop

由 旧街凉风 提交于 2020-01-06 04:52:07
问题 I am receiving rows of data every second from Kafka. For each batch of data, I am inserting into my database. My app keeps reading the last message and id of each batch. The issue here is that the promises are not running in series, but running concurrently after one batch is finished, and they keep reading the same message and id . I want each promise to have it's own message and id , as defined by the order they came in from the for-loop in the first function. I think I need to use closures

Upgrade Cassandra Version Brisk

由 ぃ、小莉子 提交于 2020-01-06 02:32:07
问题 How can I upgrade the cassandra version and thrift version in Brisk? Is there any tutorials kind of stuffs avalailble? I changed the build.properties file but on build, the version I mentioned couldn't be located at any repository. Im trying to upgrade because of Cassandra Insertion Error this issue im facing. I hope the comment mentioned there helps What is the latest version of cassandra that brisk supports? In support forums I see people mentioning, replace the jars. I don't understand

Finding the distinct count from a cassandra column using Tableau

由 走远了吗. 提交于 2020-01-06 02:12:07
问题 I am a beginner in Tableau. I have successfully connected Tableau with Cassandra. I am facing an issue now. I am trying to get the distinct count (unique) value from a given column.. The database which I have is like 17 million. (Cassandra DB) I even tried count (Distinct) as shown above. But it is not working as expected. Can anyone help me out with this? Thanks in advance. 来源： https://stackoverflow.com/questions/32889949/finding-the-distinct-count-from-a-cassandra-column-using-tableau

数据库介绍与分类

由 匆匆过客 提交于 2020-01-06 00:30:57
第1章 数据库介绍与分类 1.1 数据库介绍 什么是数据库 简单的说，数据库就是一个存放计算机数据的仓库，这个仓库是按照一定的数据结构（数据结构是指数据的组织形式或数据之间的联系）来对数据进行组织和存储的，我们可以通过数据库提供的多种方法来管理其中的数据。 1.2 数据库的种类 按照早期的数据库理论，比较流行的数据库模型有三种，分别为层次式数据库、网状数据库和关系型数据库。而在当今的互联网企业中，最常用的数据库模式主要有两种，即关系型数据库和非关系型数据库。 1.2.1 关系型数据库介绍 （1）关系型数据库由来 虽然网状数据库和层次数据库已经很好地解决了数据的集中和共享问题，但是在数据独立和抽象级别上仍有很大欠缺。用户在对这两种数据库进行存取时，仍然需要明确数据的存储结构，指出存取路径。而关系数据库就可以比较好地解决这些问题。 （2）关系型数据库介绍 关系型数据库模型是把复杂的数据结构归结为简单的二元关系（即二维表格形式）。在关系型数据库中，对数据的操作几乎全部建立在一个或多个关系表格上，通过这些关联的表格分类、合并、连接或选取等运算来实现数据的管理。 关系型数据库诞生距今已有40多年了，从理论产生到发展到实现产品，例如：常见的MySQL和Oracle数据库，oracle在数据库领域里上升到了霸主地位，形成每年高达数百亿美元的庞大产业市场，而MySQL也是不容忽视的数据库

Cassandra 之旅 (二) Getting Started

由 孤街浪徒 提交于 2020-01-05 20:19:34
一般来说学习某样东西, 我们都是找个范例照着范例先做一遍. 之后再可以通过资料, 自己使用积累去学习掌握它. 对于Cassandra, 我也不例外. 先按照官方文档部署一个简单的单节点服务出来玩一玩. Step 0: 安装JAVA环境, JDK 1.6或以上 Step 1: 下载 Cassandra 最新版本下载地址 Windows 版的 cassandra就是一个压缩包, 解压到你想安装的路径即可 Step 2: 基本配置 配置文件存放在<安装目录>/conf下面 Step 2.1: 配置cassandra需要使用的文件夹, 打开conf/cassandra.yaml文件 data_file_directories 修改成Windows下你想存放数据的路径, 如就存放到<安装目录>/data文件夹下. 注意前面的-是不能省略的 data_file_directories: - C:\Program Files (x86)\apache-cassandra-1.2.3\data commitlog_directory 修改成Windows下你想存放Log的路径 saved_caches_directory 修改成Windwos下你想存放cache的路径 Step 2.2: 打开conf/log4j-server.properties log4j.appender.R.File=

Your Cassandra cluster failed to deploy. Replica State changed to PERMANENTLY_FAILING. Replica was unhealthy 2 consecutive times

由 强颜欢笑 提交于 2020-01-05 15:18:06
问题 I tried to deploy a Cassandra Cluster using Google Compute Engine, no success. I tried several times, the error was always the same: module: DEPLOYMENT_FAILED Replica module-1234 failed with status PERMANENTLY_FAILING: Replica State changed to PERMANENTLY_FAILING. Replica was unhealthy 2 consecutive times. After following this short troubleshooting guidelines: https://cloud.google.com/solutions/cassandra/click-to-deploy#troubleshooting, the log is the following: antoniogallo88_gmail_com
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