couchdb vs cassandra

Install Python2.7 Cassandra 2.2.5 used python2.7, and CentOS 6.7 came with Python is 2.6, so to install python2.7, but can not delete 2.6 version, because Yum need to use python2.6, see CentOS Install Python2.7 2. Installation of DataStax cassandra2.2.5 http://docs.datastax.com/en/cassandra/2.2/cassandra/install/installRHEL.html 3. After the installation of the

A relational database management system (RDBMS) is the most commonly used system for storing and using data, but the scalability of these databases is not very good for large amounts of data. In recent years, the concept of NoSQL has been widely welcomed because of the increasing demand for substitute products for relational databases. The biggest motivation behind NoSQL is scalability. The NoSQL database solution provides a way to store and use large amounts of data, with less overhead, fewer

Before talking about gossip, first define what is Cassandra instance. Cassandra Instance: is a set of independent nodes in the cluster, all nodes are equivalent. Cassandra the interaction between nodes: The Gossip protocol (final consistency principle) is used to discover the location and state information of nodes in other clusters through the

The reliability, delay and consistency of the distributed system are general problems, not limited to the database, and Cassandra provides a good solution to the problem.Cassandra claims to be able to achieve the efficient access to database access across data centers, and it is implemented in a way that gives users the tradeoff between latency, throughput, and consistency. Cassandra provides two levels of

A little confused, the mind only to think of a word, "then go to learn it."I am responsible for a part of the project to use the Cassandra, at that time also looked at points, but not too deep understanding, since the "learning momentum" is sufficient, then study it well.As for the merits and demerits of NoSQL and relational databases, let's go straight to the point and finish the installation of Cassandra.Official website: http://cassandra.apache.org

Gossip is a peer -to-peer protocol that is used by nodes in a Cassandra cluster to exchange information between them. The process named gossip has more than 3 nodes exchanging data per second in the cluster , because the nodes exchange information between themselves and related nodes, so the node can quickly know the other nodes in the cluster (that is, a spread like wildfire, The concept of hundred). gossip messages are versioned, and when a message

Reference http://zhaoyanblog.com/archives/307.htmlModifying the Cassandra.yaml configuration filePut the defaultAuthenticator:allowallauthenticatorChange intoAuthenticator:passwordauthenticatorStart CassandraCQL connection, Cassandra is the default account and password./cqlsh-ucassandra-pcassandra IP PortCreate user' MyPassword ' SUPERUSER;There are two kinds of users here, one is Superuser, one is NosuperuserCqlsh after exiting, login with new userDr

Save data to Cassandra in Spark-shell:vardata = Normalfill.map (line = Line.split ("\u0005")) Data.map ( line= = (Line (0), Line (1), Line (2)) . Savetocassandra ("Cui", "Oper_ios", Somecolumns ("User_no","cust_id","Oper_code","Oper_time"))Savetocassandra method when the field type is counter, the default behavior is countCREATE TABLE CUI.INCR (Name text,Count counter,PRIMARY KEY (name))scala> var rdd = Sc.parallelize (Array (("Cui", 100))rdd:org.apa

First, set the user name and passwordModifying the Cassandra.yaml configuration filePut the defaultAuthenticator:allowallauthenticatorChange intoAuthenticator:passwordauthenticatorIf you need to log in and view the Modify permissions, you need to modifyAuthorizer:allowallauthorizerForAuthorizer:cassandraauthorizerStart CassandraCQL connection, Cassandra is the default account and password./cqlsh-u cassandra

1. If we are going to reboot Cassandra recommend that you save the data in DB before restarting Instructions: ./bin/nodetool--h 127.0.0.1 Flush 2. View the operation of each node in a clustered environment: ./bin/nodetool--h 127.0.0.1 Ring Address DCs Rack Status State Load owns Token133857208900194687050142871119212531697192.168.11.185 Datacenter1 Rack1 DownNormal? 91.45% 119317112008803869636148387431580597032192.168.11.124 datacenter1 rack1 up Nor

Spring data gives us a lot of access to the data, and then we combine Spring-data-cassandra to see how to quickly implement access to Cassandra data.Of course, the Official Handbook is a must-see, official 1.2.0RELEASE document. Prepare for the basic use of dependency:SETP1: Defines a domain model (called an entity in JPA), such as Person:Import Org.springframework.data.cassandra.mapping.PrimaryKey;Import o

This article is mainly translated from the cassandra1.2 document of Datastax. Objective: To reduce the number of sstables and Merge multiple sstables in the sequence of IOSStable: compression: In Cassandra, write new columns into the new sstable, therefore, compression is used to merge multiple sstables into one. Figure1: addingsstableswit This article is mainly translated from the cassandra1.2 document of Datastax. Objective: To reduce the number of

When crawling and storing web pages using nutch2.0 + cassandra1.0, we found that all Chinese Characters in GBK-encoded web pages are garbled during parsing and extracting text. It's strange that Chinese garbled characters have never been detected in the past in nutch1.x, because the crawler code used by nutch1.x and nutch2.x is almost the same, I guess it may be a problem when it is saved to Cassandra. After reading the source code of saving the webpa

Through the above 2 sections, we have learned about the problems encountered by RDBMS and have a basic understanding of Cassandra. The following is an introduction to the Cassandra internal simple structure.Through this chapter, you should understand: Cassandra Write Process What is sstable Cassandra R

CassandraThe data model is based on the column family (Column Family) of four or five-dimensional models. It lendsThat's it.Amazonof theDynamoand theGoogle ' sBig Table's data structure and functional characteristics, usingmemtablestored in the same way. InCassandrabefore writing the data, you need to record the log(Commitlog), and then the data begins to write toColumn Familycorresponding to thememtablein whichmemtableis a kind of according toKeyThe memory structure of the sorted data, when cer

1, Cassandra PreparationStart Cqlsh,cqlsh_host=172.16.163.131 Bin/cqlshCqlsh>create keyspace productlogs with REPLICATION = {' class ': ' Org.apache.cassandra.locator.SimpleStrategy ', ' Replication_factor ': ' 2 ' } cqlsh>CREATE TABLE productlogs.logs ( IDs uuid, app_name text, App_version text, city text, client_time timestamp, country text, created_at timestamp, int , device_id text ,int, modle_name text, Provin

Cassandra version:apache-cassandra-2.1.3Os:ubuntu 14.10Enter Cassandra Command line$./cassandra-cliView node Status$./nodetool StatusDatacenter:datacenter1=======================Status=up/down|/state=normal/leaving/joining/moving--Address Load Tokens owns Host ID RackUN 127.0.0.1 71.23 KB 256? 61129023-a5c0-4331-98ce-7

Using Thrift to allow PHP to operate Cassandra is undoubtedly a preferred solution, but configuration and operations are troublesome. We can use a php module phpcassa to operate Cassandra. Let's insert some data first: Download phpcassa: github.comdownloadshoanphpcassaphpcassa-0.1.zip extract, put it in the project Using Thrift to allow PHP to operate Cassandra

Overview of the Gossip protocolNodes in the Cassandra cluster do not have primary and secondary points, and they communicate through a protocol called gossip. Through the gossip protocol, they can know what nodes are in the cluster and how they are state. Each gossip message has a version number on it, the nodes can compare to the received messages to see which messages I need to update, what messages I have and others don't, and then talk to each oth

Cassandra 2.0 database forJava local client visit Cassandra, first establish javaproject, use MAVEN to manage.Introduce dependencies:1. Like Elasticsearch, the client now constructs a cluster object:Cluster Cluster = Cluster.builder () . Addcontactpoint ("Your IP") . Build (); Metadata Metadata = Cluster.getmetadata (); System.out.printf ("Connected to cluster:%s\