入門指南單節(jié)點(diǎn)

1、Cassandra 1.1.2入門指南Cassandra is a highly scalable, eventually consistent, distributed, structured key-value store. Cassandra是高擴(kuò)展性的、最終一致性的、分布式的、結(jié)構(gòu)化的key/value存儲(chǔ)系統(tǒng)。For more information see //cassandra/Project description-Cassandra brings together the distr

2、ibuted systems technologies from Dynamo and the data model from Google's BigTable. Like Dynamo, Cassandra is eventually consistent. Like BigTable, Cassandra provides a ColumnFamily-baseddata model richer than typical key/value systems.Cassandra結(jié)合了源自Dynamo的分布式系統(tǒng)技術(shù)（存儲(chǔ)模型）與源自Google BigTable的數(shù)據(jù)組織結(jié)構(gòu)和訪

3、問(wèn)控制技術(shù)（數(shù)據(jù)模型）。Cassandra采用了Dynamo的最終一致性原則，采用了BigTable的基于ColumnFamily的數(shù)據(jù)模型（優(yōu)于典型的key/value系統(tǒng)數(shù)據(jù)模型）。keyspace類似于關(guān)系數(shù)據(jù)庫(kù)中的database。ColumnFamily類似于關(guān)系數(shù)據(jù)庫(kù)中的關(guān)系relation。key類似于關(guān)系數(shù)據(jù)庫(kù)中的主鍵primary key。column類似于關(guān)系數(shù)據(jù)庫(kù)中的列名column name。value類似于關(guān)系數(shù)據(jù)庫(kù)中一個(gè)行列交匯處的值value。Requirements- * Java >= 1.6 (OpenJDK and Sun have been tes

4、ted)Getting started-This short guide will walk you through getting a basic one node cluster upand running, and demonstrate some simple reads and writes.構(gòu)建并運(yùn)行只有一個(gè)節(jié)點(diǎn)的集群，然后演示簡(jiǎn)單的讀寫。在Linux下執(zhí)行命令如下： * tar -zxvf apache-cassandra-$VERSION.tar.gz * cd apache-cassandra-$VERSION * sudo mkdir -p /var/log/cassand

5、ra * sudo chown -R whoami /var/log/cassandra * sudo mkdir -p /var/lib/cassandra * sudo chown -R whoami /var/lib/cassandraNote: The sample configuration files in conf/ determine the file-system locations Cassandra uses for logging and data storage. You are free tochange these to suit your own environ

6、ment and adjust the path namesused here accordingly.$cassandra_HOME/conf/目錄下的cassandra.yaml配置文件設(shè)置了用于記錄日志和數(shù)據(jù)存儲(chǔ)的文件系統(tǒng)的位置?？梢匀我庑薷牡狡渌窂健? directories where Cassandra should store data on disk.data_file_directories: - /var/lib/cassandra/data# commit logcommitlog_directory: /var/lib/cassandra/commitlog補(bǔ)充：Li

7、nux下執(zhí)行bin/cassandra啟動(dòng)Cassandra之前，需要設(shè)置如下環(huán)境變量，否則會(huì)拋出NoClassDefFoundError等異常：# CLASSPATH - A Java classpath containing everything necessary to run.Java類路徑，包含運(yùn)行所需的所有jar(通過(guò)bin/cassandra.in.sh設(shè)置)# JVM_OPTS - Additional arguments to the JVM for heap size, etcJVM的其他參數(shù)，如堆大小等(通過(guò)conf/cassandra-env.sh設(shè)置，執(zhí)行bin/ca

8、ssandra會(huì)調(diào)用該腳本)。# CASSANDRA_CONF - Directory containing Cassandra configuration files.Cassandra配置文件目錄(通過(guò)bin/cassandra.in.sh設(shè)置)使環(huán)境變量立刻生效：source bin/cassandra.in.sh查看環(huán)境變量：echo $CLASSPATHNow that we're ready, let's start it up!Linux下打開(kāi)終端窗口，通過(guò)腳本啟動(dòng)Cassandra，執(zhí)行如下： * bin/cassandra -fUnix: Running th

9、e startup script with the -f argument will causeCassandra to remain in the foreground and log to standard out.注意：Linux下啟動(dòng)Cassandra使用-f參數(shù)，可以使Cassandra前臺(tái)運(yùn)行，以方便查看輸出日志。其他還有如下兩個(gè)參數(shù)：# -p <filename>: log the pid to a file (useful to kill it later)將Cassandra的進(jìn)程ID（pid）記錄到日志文件（后續(xù)可以通過(guò)kill <pid>停止Cas

10、sandra）# -v: print version string and exit打印出版本信息并停止Windows: bincassandra.bat runs in the foreground by default. Toinstall Cassandra as a Windows service, download Procrun from/daemon/procrun.html, set the PRUNSRVenvironment variable to the full path of prunsrv (e.g.,C:procru

11、nprunsrv.exe), and run "bincassandra.bat install".Similarly, "uninstall" will remove the service.Now let's try to read and write some data using the command line client.下面就可以使用命令行客戶端讀寫數(shù)據(jù)了。打開(kāi)新的終端窗口，執(zhí)行如下命令： * bin/cassandra-cli -host localhostThe command line client is interacti

12、ve so if everything worked you shouldbe sitting in front of a prompt.該命令行客戶端具有交互性，如果一切正常，將會(huì)出現(xiàn)如下提示。 Connected to: "Test Cluster" on localhost/9160 Welcome to cassandra CLI. Type 'help;' or '?' for help. Type 'quit;' or 'exit;' to quit. defaultunknown As the b

13、anner says, you can use 'help;' or '?' to see what the CLI has tooffer, and 'quit;' or 'exit;' when you've had enough fun. But lets trysomething slightly more interesting.在出現(xiàn)的提示符后面執(zhí)行如下操作： defaultunknown create keyspace Keyspace1; ece86bde-dc55-11df-8240-e700f669bc

14、fc defaultunknown use Keyspace1; Authenticated to keyspace: Keyspace1 defaultKeyspace1 create column family Users with comparator=UTF8Type and default_validation_class=UTF8Type and key_validation_class=UTF8Type; 737c7a71-dc56-11df-8240-e700f669bcfc defaultKS1 set Usersjsmithfirst = 'John' Va

15、lue inserted. defaultKS1 set Usersjsmithlast = 'Smith' Value inserted. defaultKS1 set Usersjsmithage = long(42); Value inserted. defaultKS1 get Usersjsmith; => (column=last, value=Smith, timestamp=1287604215498000) => (column=first, value=John, timestamp=1287604214111000) => (column

16、=age, value=42, timestamp=1287604216661000) Returned 3 results.If your session looks similar to what's above, congrats, your single nodecluster is operational! But what exactly was all of that? Let's break itdown into pieces and see. set Usersjsmithfirst = 'John' _ key _ value _ colu

17、mn _ column familyData stored in Cassandra is associated with a column family (Users),which in turn is associated with a keyspace (Keyspace1). In the exampleabove, we set the value 'John' in the 'first' column for key 'jsmith'.For more information on the Cassandra data model be sure to checkout /cassandra/Da