Cassandra installation and cql testing

One: Download cassandra

http://archive.apache.org/dist/cassandra/

I am using 2.1.8, 3.9 requires java8

wget http://archive.apache.org/dist/cassandra/2.1.8/apache-cassandra-2.1.8-bin.tar.gz

Two: decompress

tar -zxvf  apache-cassandra-2.1.8-bin.tar.gz

Three: create a new directory

mkdir /usr/local/cassandra/data

mkdir /usr/local/cassandra/commitlog

mkdir /usr/local/cassandra/saved_caches

Four: Modify the configuration file

vi conf / cassandra.yaml

data_file_directories:

 

     - /usr/local/cassandra/data

commitlog_directory: /usr/local/cassandra/commitlog

saved_caches_directory: /usr/local/cassandra/saved_caches

 

vi conf/cassandra-env.sh

MAX_HEAP_SIZE="2G"

 

144 HEAP_NEWSIZE="800M"

 

Five: run

cd bin

./cassandra 

 

 

 

Six: start cql

cd bin

./cqlsh 

 

Cassandra CQL usage

 

CREATE KEYSPACE

There are two strategies for keyspace, one is SimpleStrategyand the other isNetworkTopologyStrategy

• SimpleStrategy
  In this mode, a replication strategy needs to be specified, and several copies of data are redundant, such as:

• create KEYSPACE demodb WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 2};

• NetworkTopologyStrategy
  This mode is based on data center-rack. To create a KEYSPACE based on this mode, you must configure this mode in the configuration file, otherwise an exception will be reported:
  Unable to complete request: one or more nodes were unavailable The
  creation code is as follows:

• CREATE KEYSPACE demodb WITH REPLICATION = { 'class' : 'NetworkTopologyStrategy', 'dc1' :3 };

---

table operations

• create table

• create table blog(id timeuuid , title text, content text, tags list<text>, category text, primary key(id));

• insert

• INSERT INTO  blog (id, title , tags ) VALUES ( now(), 'cassandra table test', ['cassandra','table']);

• using ttl If used together with if not exists or if exists, if should be placed before ttl

• INSERT INTO  blog (id, title , tags ) VALUES ( now(), 'cassandra table test', ['cassandra','table']) 

• USING TTL 222; --单位为秒这个时间是针对整行起作用
  UPDATE BLOG USING TTL=33 SET TITLE='SS' WHERE ID=1; --针对这个字段起作用，而不是整行数据

• Only when the operations in the batch batch are successful will these operations be executed

• BEGIN BATCH
  
  INSERT INTO  blog (id, title , tags ) VALUES ( now(), 'cassandra table test', ['cassandra','table']) USING TTL 222; --单位为秒这个时间是针对整行起作用
  UPDATE BLOG USING TTL=33 SET TITLE='SS' WHERE ID=1; --针对这个字段起作用，而不是整行数据
  APPLY BATCH;

http://ju.outofmemory.cn/entry/210437