1. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 1 : Flexible Database Clustering Middleware Emmanuel Cecchet – INRIA Julie Marguerite – ObjectWeb Willy Zwaenepoel – EPFL

2. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 2 Internet  Database tier should be –scalable –highly available –without modifying the client application –database vendor independent –on commodity hardware Motivations JDBC

3. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 3 Scaling the database tier – Alternative 1 (master-slave) Internet Web frontend App. server  Cons –failover time on master failure –scalability Master

4. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 4 Scaling the database tier – Alternative 2 (SMP) Internet Web frontend App. server Well-known database vendor here Database Well-known hardware + database vendors here  Cons –Cost –Scalability limit

5. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 5 Scaling the database tier – Alternative 3 (shared disks) Internet Web frontend App. server Database Disks Another well-known database vendor  Cons –still expensive hardware –availability

6. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 6 Outline  C-JDBC architecture  High availability  Use cases  Conclusion

7. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 7 architectural overview JVM Application server MySQL JDBC driver MySQL database JVM C-JDBC JDBC driver C-JDBC controller JVM

8. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 8 basic concepts JVM  2 components –C-JDBC driver –C-JDBC controller –100% Java implementation  Read-one, Write all approach  Tunable replication –full partitioning –full replication –partial replication

9. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 9 Functional overview connect myDB connect login, password execute SELECT * FROM t

10. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 10 Functional overview execute INSERT INTO t …

11. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 11 Outline  C-JDBC architecture  High availability  Use cases  Conclusion

12. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 12 Failures  No 2 phase- commit –parallel transactions –failed nodes are automatically disabled execute INSERT INTO t …

13. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 13 Restoring a backend  Updates stored in the recovery log  Database dumps associated to checkpoints

14. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 14 Synchronization  Replay missing updates from log

15. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 15 Healed Cluster  Re-enable backend when done

16. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 16 Vertical scalability  Addresses JVM scalability issues  Distributing large number of connections on many backends

17. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 17 Controller replication  Prevent the controller from being a single point of failure  Group communication for controller synchronization

18. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 18 Controller replication jdbc:cjdbc://node1,node2/myDB Total order reliable multicast

19. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 19 Mixing horizontal & vertical scalability

20. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 20 Current limitations  Replication granularity is table  No distributed joins  Network partition with replicated controllers  JDBC only –support of PHP, Perl, ODBC through wrappers or bridges –partial support of JDBC 3.0

21. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 21 Other features  SSL support  Support for heterogeneous databases  SQL monitoring  JMX based administration console  Request player

22. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 22 Outline  C-JDBC architecture  High availability  Use cases  Conclusion

23. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 23 Budget High Availability  High availability infrastructure “on a budget”  Typical eCommerce setup  http://www.budget-ha.com

24. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 24 OpenUSS: University Support System  eLearning  High availability  Portability –Linux, HP-UX, Windows –InterBase, Firebird, PostgreSQL, HypersonicSQL  http://openuss.sourceforge.net

25. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 25 Flood alert system  Disaster recovery  Independent nodes synchronized with C-JDBC  VPN for security issues  http://floodalert.org

26. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 26 J2EE benchmarking  Large scale J2EE clusters  http://jmob.objectweb.org Interne t emulated users

27. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 27 Outline  C-JDBC architecture  High availability  Use cases  Conclusion

28. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 28 Conclusion  C-JDBC: Flexible Database Clustering Middleware –scalable –highly available –without modifying the client application –database vendor neutral –on commodity hardware  LPGL software hosted by ObjectWeb

29. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 29 Q&A _________ Thanks to all users and contributors... http://c-jdbc.objectweb.org

30. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 30 TPC-W benchmark (Amazon.com)  Nearly linear speedups with the shopping mix

31. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 31 Result cache  Cache contains a list of SQL->ResultSet  Policy defined by queryPattern->Policy  3 policies –EagerCaching: variable granularities for invalidations –RelaxedCaching: invalidations based on timeout –NoCaching: never cached RUBiS bidding mix with 450 clients No cacheCoherent cache Relaxed cache Throughput (rq/min)389241844215 Avg response time801 ms284 ms134 ms Database CPU load100%85%20% C-JDBC CPU load-15%7%

32. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 32 Recovery log  All updates are stored in the recovery log  Database dumps associated to checkpoints

33. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 33 Making new checkpoints  Disable one backend to have a coherent snapshot  Mark the new checkpoint entry in the log  Use Octopus to store the dump

34. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 34 Making new checkpoints  Replay missing updates from log

35. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 35 Making new checkpoints  Re-enable backend when done

36. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 36 Handling a backend failure  A node fails!  Automatically disabled but should be fixed or changed by administrator

37. Usenix Annual Conference, Freenix track – June 2004 – c-jdbc@objectweb.org 37 Fault tolerant recovery log UPDATE statement