2. 2 Proprietary & Confidential What is Sharding Benefits of Sharding Alternatives of Sharding When to start Sharding Agenda

3. 3 Proprietary & Confidential Wikipedia: – Horizontal partitioning is a database design principle whereby rows of a database table are held separately, rather than splitting by columns (which is what normalization and vertical partitioning do, to differing extents). Each partition forms part of a shard, which may in turn be located on a separate database server or physical location.normalizationvertical partitioning What Is Sharding

4. 4 Proprietary & Confidential Example IDFirst nameLast name 100StevenKing 101NeenaKochhar 102LexDe Haan 103AlexanderHunold 104BruceErnst 105DavidAustin 106ValliPataballa IDFirst nameLast name 102LexDe Haan 105DavidAustin IDFirst nameLast name 100StevenKing 103AlexanderHunold 106ValliPataballa IDFirst nameLast name 101NeenaKochhar 104BruceErnst

5. 5 Proprietary & Confidential Every big web site you can think of FaceBook, Twitter, Flickr to name a few Who Uses Sharding

6. 6 Proprietary & Confidential Sharding lets you: – Scale Out database Increate number of concurrent transactions – Improve performance Decrease latency – Make the database elastic Benefits Of Sharding

7. 7 Proprietary & Confidential Size – Table size is reduced – Index size is reduced – More in memory – less disk access Hits – Isolation is a pain – Less hits per database – less isolation Performance Improvement

8. 8 Proprietary & Confidential Database needs to maintain copies of the data per user, to ensure transaction boundaries – More users – more copies – Longer transactions – more copies Indexes are stored on actual data – Copies are problematic See here for complete explanation - http://www.scalebase.com/isolation-levels-in- relational-databases/ http://www.scalebase.com/isolation-levels-in- relational-databases/ Sharding helps reduces # of transaction per database shard Database Isolation

9. 9 Proprietary & Confidential Tuning Scale Up Read/Write Splitting NoSQL Alternatives For Sharding

10. 10 Proprietary & Confidential There are many ways to tune your database Allot of data online, check out this post – http://forge.mysql.com/wiki/Top10SQLPerformanceTips http://forge.mysql.com/wiki/Top10SQLPerformanceTips Database Tuning

11. 11 Proprietary & Confidential innodb_buffer_pool_size – Holds the data and indexes of tables in memory. – Bigger buffer results in faster row lookups. – The bigger the better. – Default – 8M Query Cache – Keeps the result of queries in memory until they are invalidated by writes. – query_cache_size total size of memory available to query caching – query_cache_limit the maximum number of kilobytes one query may be in order to be cached. – query_cache_size = 128MB – query_cache_limit = 4MB Database Tuning – Some Examples

12. 12 Proprietary & Confidential Usually DB gets the strongest servers However – there is a limit to how much performance gains you can get from increasing hardware Some data: Scaling Up Hardware http://www.mysqlperformanceblog.com/2011/01/26/modeling-innodb-scalability-on- multi-core-servers/ http://www.mysqlperformanceblog.com/2011/01/26/modeling-innodb-scalability-on- multi-core-servers/

13. 13 Proprietary & Confidential Solid State Drive – Better latency and access time than regular HDD – Cost more per GB (but prices are dropping) Vadim Tkachenko from Percona gave a great lecture on SSD at MySQL Conf 2011 – (see slides at http://en.oreilly.com/mysql2011/public/schedule/detail/171 17) http://en.oreilly.com/mysql2011/public/schedule/detail/171 17 – Claims you can expect up to X7 performance from SSD SSD

14. 14 Proprietary & Confidential Write to MySQL master, read from 1 (or more) slaves Excellent read scaling Many issues: – Since replication is a-synchronous – read might not be up to date – Transactions create stickiness – Code changes Read/Write Splitting

15. NoSQL A term used to designate databases which differ from classic relational databases in some way. These data stores may not require fixed table schemas, and usually avoid join operations and typically scale horizontally. Academics and papers typically refer to these databases as structured storage, a term which would include classic relational databases as a subset. http://en.wikipedia.org/wiki/NoSQL

16. NoSQL Types Key/Value – A big hash table – Examples: Voldemort, Amazon Dynamo Big Table – Big table, column families – Examples: Hbase, Cassandra Document based – Collections of collections – Examples: CouchDB, MongoDB Graph databases – Based on graph theory – Examples: Neo4J Each solves a different problem

17. NO-SQL http://browsertoolkit.com/fault-tolerance.png

18. 18 Proprietary & Confidential Database Size (including indexes) > available memory – When databases go to disk, bad things happen Too many hits/second High write/read ration When To Start Sharding

19. 19 Proprietary & Confidential Start small, end big TCO – Management – Backup – Time to market Downsides of Sharding

20. 20 Proprietary & Confidential Sharding – no hassle No hidden costs – New features – Easy administration Benefits Of ScaleBase

21. 21 Proprietary & Confidential Join us at our next webinar, Scaling MySQL on EC2, on January 10 th, 2012. Thank You