Slides from 10/26/2011 Cassandra Austin Meetup group

3. CAP Theorem C onsistency A vailability P artition Tolerance “ Thou shalt have but 2” - Conjecture made by Eric Brewer in 2000 - Published as formal proof in 2002 - See: http://en.wikipedia.org/wiki/CAP_theorem for more

5. Generally complements another system(s) (Not intended to be one-size-fits-all) *** You should always use the right tool for the right job anyway

6. How does this differ from an RDBMS?

7. How does this differ from an RDBMS? Substantially.

8. vs. RDBMS - No Joins Unless: - you do them on the client - you do them via Map/Reduce

9. vs. RDBMS - Schema Optional (Though you can add meta information for validation and type checking) *** Supports secondary indexes too: “ … WHERE state = 'TX' ”

10. vs. RDBMS - Prematerialized and Transaction-less - No ACID transactions - Limited support for ad-hoc queries

11. vs. RDBMS - Prematerialized and Transaction-less - No ACID transactions - Limited support for ad-hoc queries *** You are going to give up both of these anyway when you shard an RDBMS ***

13. vs. RDBMS - Shared-Nothing Architecture Every node plays the same role: no masters, no slaves, no special nodes *** No single point of failure

23. - Controls replication

24. Column Family

25. - Similar to a table

26. - Columns ordered by name

28. Dynamic Column Family

29. - Pre-calculated query results

30. Nothing stopping you from mixing them!

35. Using a Client Hector Client: http://hector-client.org - Most popular Java client - In use at very large installations - A number of tools and utilities built on top - Very active community - MIT Licensed *** like any open source project fully dependent on another open source project it has its worts

45. - Merge on read

46. - Sstables are immutable

47. - Highest timestamp wins

49. -------------------

50. RowKey: CA Burlingame

51. => (column=650, value=33372e3537783132322e3334, timestamp=1310340410528000)

52. -------------------

53. RowKey: TX Austin

54. => (column=202, value=33302e3237783039372e3734, timestamp=1310143852392000)

55. => (column=203, value=33302e3237783039372e3734, timestamp=1310143852444000)

56. => (column=204, value=33302e3332783039372e3733, timestamp=1310143852448000)

57. => (column=205, value=33302e3332783039372e3733, timestamp=1310143852453000)

58. => (column=206, value=33302e3332783039372e3733, timestamp=1310143852457000)

60. -------------------

61. RowKey: CA Burlingame

62. -------------------

63. RowKey: TX Austin

64. => (column=202, value=33302e3237783039372e3734, timestamp=1310143852392000)

65. => (column=203, value=33302e3237783039372e3734, timestamp=1310143852444000)

66. => (column=204, value=33302e3332783039372e3733, timestamp=1310143852448000)

67. => (column=205, value=33302e3332783039372e3733, timestamp=1310143852453000)

68. => (column=206, value=33302e3332783039372e3733, timestamp=1310143852457000)

70. . . .

71. -------------------

72. RowKey: 202230

73. -------------------

74. . . .

76. class="me.prettyprint.cassandra.service.CassandraHostConfigurator">

77. <constructor-arg value=&quot;localhost:9170&quot;/>

78. </bean>

79. <bean id=&quot;cluster&quot; class=&quot;me.prettyprint.cassandra.service.ThriftCluster&quot;>

80. <constructor-arg value=&quot;TestCluster&quot;/>

81. <constructor-arg ref=&quot;cassandraHostConfigurator&quot;/>

82. </bean>

83. <bean id=&quot;consistencyLevelPolicy&quot; class=&quot;me.prettyprint.cassandra.model.ConfigurableConsistencyLevel&quot;>

84. <property name=&quot;defaultReadConsistencyLevel&quot; value=&quot;ONE&quot;/>

85. </bean>

86. <bean id=&quot;keyspaceOperator&quot; class=&quot;me.prettyprint.hector.api.factory.HFactory&quot;

87. factory-method=&quot;createKeyspace&quot;>

88. <constructor-arg value=&quot;Keyspace1&quot;/>

89. <constructor-arg ref=&quot;cluster&quot;/>

90. <constructor-arg ref=&quot;consistencyLevelPolicy&quot;/>

91. </bean>

92. <bean id=&quot;simpleCassandraDao&quot; class=&quot;me.prettyprint.cassandra.dao.SimpleCassandraDao&quot;>

93. <property name=&quot;keyspace&quot; ref=&quot;keyspaceOperator&quot;/>

94. <property name=&quot;columnFamilyName&quot; value=&quot;Standard1&quot;/>

95. </bean>

97. https://github.com/rantav/hector/wiki/Hector-Object-Mapper-%28HOM%29

98. Hector JPA:

99. https://github.com/riptano/hector-jpa

102. *** Still some caveats and missing features

104. - see portfolio_example sub project

106. - Spring Framework's JdbcTemplate

107. - DAO class with associated domain objects

108. - Junit

109. - Spring Framework's SpringJUnit4ClassRunner (context setup and injection)

110. - EmbededServerHelper from hector-test (manage Cassandra lifecycle, directories and configuration)

112. - Cluster name, keyspace and at least 1 host required

113. - Additional settings for:

114. * fail over semantics

115. * automatic host discovery

116. * timeout counters and thresholds

118. auth= &quot;Container&quot;

119. type= &quot;me.prettyprint.cassandra.api.Keyspace&quot;

120. factory= &quot;me.prettyprint.cassandra.jndi.CassandraClientJndiResourceFactory&quot;

121. hosts= &quot;cass1:9160,cass2:9160,cass3:9160&quot;

122. user= &quot;user&quot;

123. password= &quot;passwd&quot;

124. keyspace=&quot; Keyspace1&quot;

125. clusterName= &quot;Test Cluster&quot;

126. maxActive= &quot;20&quot;

127. maxWaitTimeWhenExhausted= &quot;10&quot;

128. failoverPolicy= &quot;ON_FAIL_TRY_ALL_AVAILABLE&quot;

129. autoDiscoverHosts= &quot;true&quot;

130. runAutoDiscoveryAtStartup= &quot;true&quot; />

132. id= &quot;ds&quot; >

133. <property name= &quot;clusterName&quot; value= &quot;TestCluster&quot; />

134. <property name= &quot;keyspaceName&quot; value= &quot;PortfolioDemo&quot; />

135. <property name= &quot;hosts&quot; value= &quot;127.0.0.1:9170&quot; />

136. </bean>

137. <bean class= &quot;org.springframework.jdbc.core.JdbcTemplate&quot;

138. id=&quot; jdbcTemplate&quot; >

139. <constructor-arg ref= &quot;ds&quot; />

140. </bean>

142. &quot;BEGIN BATCH &quot;

143. + &quot;INSERT INTO Portfolios (KEY, BLU, CJS, DAL) VALUES (168,'19', '7', '38') &quot;

144. + &quot;INSERT INTO Portfolios (KEY, BSX, CHK, DNB, MCI, SR) VALUES (236,'32', '27', '7','8','3') &quot;

145. + &quot;APPLY BATCH&quot; ;

146. ...

147. jdbcTemplate.execute(PORTFOLIOS_INSERT); Inserting Test Data

149. CassandraResultSet crs = (CassandraResultSet)rs;

150. Stock stock = new Stock();

151. stock.setTicker(new String(crs.getKey()));

152. stock.setPrice(crs.getDouble(&quot;price&quot;));

153. return stock;

154. }

155. See PortfolioDao#loadStocks Reading Data via RowMapper

157. CCM localhost cassandra cluster https://github.com/pcmanus/ccm

161. - Bank account:

162. “ on values over $10,000, wait to here from all replicas”

163. - Distributed Shopping Cart:

164. Show a confirmation page to verify order resolution

165. *** What is your appetite for risk?

168. ***But In an append-only system, we don't do updates

170. - Look for idempotence and asynchronicity in your business processes

171. - If it's not in the API, you are probably doing it wrong

172. - Seek death is still possible if you model incorrectly

175. Apache Cassandra project wiki: http://wiki.apache.org/cassandra/

176. “ The Dynamo Paper”

177. http://www.allthingsdistributed.com/files/amazon-dynamo-sosp2007.pdf

178. P. Helland. Building on Quicksand

179. http://arxiv.org/pdf/0909.1788

180. P. Helland. Life Beyond Distributed Transactions

181. http://www.ics.uci.edu/~cs223/papers/cidr07p15.pdf

182. S. Anand. “Netflix's Transition to High-Availability Storage Systems”

183. http://media.amazonwebservices.com/Netflix_Transition_to_a_Key_v3.pdf

184. “ The Megastore Paper”

185. http://research.google.com/pubs/archive/36971.pdf