M|18 Deep Dive: InnoDB Transactions and Replication

1. Deep Dive: Replication
From basics into subtleties of binary logging and
multi-threaded applier
Andrei Elkin, Senior MariaDB
developer

2. Why to dive deep?
Designed in MySQL even before transaction. Serves a number of critical missions
including:
● Backup and point-in-time recovery
● Load balancer
● Auditing
● Error case analysis

4. Replication conceptually is 2PC

5. Transaction state transaction

6. Binary logging

7. Binlog group commit

8. Binlog Group Commit ordered

9. binary logging: event group

10. event group: example

11. Events shipping: Dump thread

12. Events receiving: IO thread

13. No failover without ...

14. GTID idea

15. GTID: required in Multi-Source replication

16. GTID definition

17. GTID and Multi-Sourced Replication
Transactions from different domains are executed independently

18. Events execution on slave: single-threaded mode

19. Events execution: parallel scheduling

20. Events execution: ordered commit

21. GTID execution: gtid_slave_pos table

23. Recovery: committed data may be lost

24. Recovery without Binlog_checkpoint

25. Recovery: server crash

26. Recovery: post-restart decisions

27. Ongoing and perspective projects
1) XA replication MDEV-7974
2) Eager replication as follow-up XA replication
3) Parallel slave group commit
4) Relay-log-less slave
5) Committed GTID tracker by engine
6) Binlog-less “relay” slave in chain replication
7) Consensus protocol on membership in replication configuration
8) E.g Paxos-like mode semi-sync

28. Ongoing: XA replication MDEV-7974

29. Follow-ups: active replication

30. Improvement ideas: slave group commit

31. References:
https://mariadb.com/kb/en/library/replication-overview/
https://kristiannielsen.livejournal.com/16826.html
https://kristiannielsen.livejournal.com/16382.html
MariaDB for Advanced DBAs. MariaDB Training, MariaDB (c)
Database replication techniques: a three parameter classification
M. Wiesmann ; F. Pedone ; A. Schiper ; B. Kemme ; G. Alonso