Intro to MySQL Master Slave Replication
- 1. Intro to MySQL Master Slave Replication Satej Kumar Sahu Mindfire Solutions
- 2. Contents • What is Replication? • Concept of Master and Slave • Advantages of Replication • Methods of Replication • How event based replication works? • Demo setup of master slave replication in MySQL • Code/config setup from the start for allowing app level support for master-slave setups later • Scenarios best for this setup/strategy • Conclusion • References
- 3. What is Replication? • Replication enables data from one MySQL database server (the master) to be copied to one or more MySQL database servers (the slaves). • By default asynchronous.
- 4. Concept of Master and Slave
- 5. Advantages of Replication • Scale-out solutions • Data security • Analytics • Long-distance data distribution
- 6. Methods of Replication • Traditional method based on replicating events from the master's binary log, and requires the log files and positions in them to be synchronized between master and slave. - Types of events: Row based (default) or statement based or mixed type. • Newer method based on global transaction identifiers (GTIDs) which is transactional.
- 7. How event based Replication works?
- 8. Demo setup of master slave replication in MySQL • Two AWS instances with port 3306 open for mysql on master instance.
- 9. Code/config setup from the start for allowing app level support for master-slave setups later • Database access layer code should have been properly abstracted/modularized • safe_writer_connect() safe_reader_connect() safe_reader_statement() safe_writer_statement() • Important thing is to have a unified interface for connecting for reads, connecting for writes, doing a read, and doing a write. • May be a painful and scary process at first. The code is much easier to maintain, and adding troubleshooting options is trivial. You need modify only one or two functions; for example, to log how long each statement took, or which statement among those issued gave you an error. • Also, you can create a user for write only and read only privileges to connect to master and slave for added separation of concern layer.
- 10. Scenarios best for this setup/strategy • Most of the cases you would not need it. A good designed, optimised, normalized database would not require it normally. • MySQL replication is most beneficial for a system that processes frequent reads and infrequent or low number of writes/updates. • Answering the following questions should help you decide whether and by how much replication will improve the performance of your system - read/write ratio on your system? - How much more write load can one server handle if you reduce the reads? - For how many slaves do you have bandwidth available on your network? • Examples: - Ecommerce sites - Newspaper sites - Online library sites - Blogging sites • Browsing happens much in comparison to writes.
- 11. Conclusion • In most of the case, given good database design and optimisations and use of indexes, you would not need replication in most of the cases. • But if you need to scale out due to large number of reads, you should go for it :)
- 12. References • http://dev.mysql.com/doc/refman/5.7/en/replication.html • https://www.percona.com/blog/2013/01/09/how-does- mysql-replication-really-work/ • https://dev.mysql.com/doc/refman/5.7/en/faqs- replication.html • https://dev.mysql.com/doc/refman/5.7/en/faqs- replication.html#faq-replication-replication-how-benefits- me
- 13. any?
- 14. Thank You :)