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MySQL Storage Engines Landscape


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Presented at SCALE10x, in Los Angeles, January 2012

Presented at SCALE10x, in Los Angeles, January 2012

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  • 1. The MySQL Storage Engines Landscape Colin Charles, Monty Program Ab / / @bytebot on Twitter SCALE10x, Los Angeles, CA, USA 20 January 2012
  • 2. whoami• Chief Evangelist, MariaDB• Formerly of MySQL AB/Sun Microsystems• Past lives included FESCO (Fedora Project),
  • 3. Agenda• What is a storage engine?• What makes storage engines different?• What storage engines are available?• Usage examples• The Storage Engine API
  • 4. The many storage engines...• MyISAM • NDB • OpenOLAP• Q4M • SolidDB • Merge• RitmarkFS • AWS • XtraDB• ha_memcache • Nitro • mysql-filesystem-engine• Federated/FederatedX • Aria • ScaleDB• Infobright • DDE • Spider• PBXT • My BLOB Streaming • Groonga• InnoDB • Memory • vpformysql• myhttp • ARCHIVE • Tokutek• mdbtools • CSV • ...and many more...• Blackhole • SphinxSE
  • 5. Engines in the ecosystem• MySQL/MariaDB/Percona Performance Server uses MyISAM as default pre-5.5• MySQL: default > 5.5 - InnoDB, with MyISAM handling temporary tables• MariaDB: default > 5.5 - XtraDB, with Aria handling temporary tables• Percona Server: default > 5.5 - XtraDB, with MyISAM handling temporary tables• Drizzle: some engines exist, MyISAM for temporary tables only, InnoDB by default
  • 6. Pluggable Engine Architecture
  • 7. Value Proposition• No other database offers this capability• Unmatched flexibility + customisation potential • MEMORY engine for performance/routine lookup data• Right storage engine can improve performance in many applications • ARCHIVE compresses data, up to 80%• Partners & community benefit from this
  • 8. What makes storage engines different?• Storage: how the data is stored on disk• Indexes: improves search operations• Memory usage: improves data access for speed• Transactions: protects the integrity of your data (ACID)
  • 9. Native engines in MySQL 5mysql> show engines;+------------+---------+----------------------------------------------------------------+| Engine | Support | Comment |+------------+---------+----------------------------------------------------------------+| MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance || MEMORY | YES | Hash based, stored in memory, useful for temporary tables || InnoDB | YES | Supports transactions, row-level locking, and foreign keys || BerkeleyDB | YES | Supports transactions and page-level locking || BLACKHOLE | NO | /dev/null storage engine (anything you write to it disappears) || EXAMPLE | NO | Example storage engine || ARCHIVE | NO | Archive storage engine || CSV | NO | CSV storage engine || ndbcluster | NO | Clustered, fault-tolerant, memory-based tables || FEDERATED | NO | Federated MySQL storage engine || MRG_MYISAM | YES | Collection of identical MyISAM tables || ISAM | NO | Obsolete storage engine |+------------+---------+----------------------------------------------------------------+12 rows in set (0.01 sec)
  • 10. Native engines in MariaDB 5.1MariaDB [(none)]> show engines;+------------+---------+--------------------------------------------------------------------------------------------------+--------------+------+------------+| Engine | Support | Comment | Transactions | XA | Savepoints |+------------+---------+--------------------------------------------------------------------------------------------------+--------------+------+------------+| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO || MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO || FEDERATED | YES | FederatedX pluggable storage engine | YES | NO | YES || MARIA | YES | Crash-safe tables with MyISAM heritage | YES | NO | NO || CSV | YES | CSV storage engine | NO | NO | NO || MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO || ARCHIVE | YES | Archive storage engine | NO | NO | NO || MyISAM | DEFAULT | Default engine as of MySQL 3.23 with great performance | NO | NO | NO || InnoDB | YES | XtraDB engine based on InnoDB plugin. Supports transactions, row-level locking, and foreign keys | YES | YES | YES || PBXT | YES | High performance, multi-versioning transactional engine | YES | YES | NO |+------------+---------+--------------------------------------------------------------------------------------------------+--------------+------+------------+10 rows in set (0.00 sec)
  • 11. Some notes post-5.1• dynamically loadable storage engines - i.e. they are pluggable • Embedded InnoDB (now, see HailDB) • e.g. you can load SphinxSE for FTS• Federated disabled (FederatedX in MariaDB)• Native partitioning (RANGE, LIST, HASH, KEY) available (no need for MERGE tables)
  • 12. Commercial engines in the ecosystem• InfoBright - data warehousing applications• TokuDB - uses Fractal Trees, for Big Data analysis, online schema changes, hot indexes/columns• ScaleDB - cloud-friendly scalability, with load balancing+high availability
  • 13. Using different engines• Create a table with a specified engine • CREATE TABLE t1 (..) ENGINE=XtraDB;• Changing existing tables • ALTER TABLE t1 ENGINE=Aria;• SHOW ENGINES;
  • 14. Transactional vs. non- transactional• Transaction-safe tables • Update fails? Changes (InnoDB) have advantages reverted over non-transaction safe tables (MyISAM): • Concurrency - tables w/ many update + • server crash? Automatic concurrent reads recovery, or a backup +transaction log • Disadvantages in today’s environments (transaction • ROLLBACK can be overhead = slower), more executed to ignore disk space requirements, changes more memory to perform updates don’t seem like they apply any longer
  • 15. Indexes• Tree Indexes • Hash Indexes (MEMORY, NDB, InnoDB) • B-Trees • If table fits entirely in • B+Trees (InnoDB) memory, fastest way to perform queries is a hash • T-Trees (NDB) index • Red-black binary trees • InnoDB has an internal (MEMORY) adaptive hash index. InnoDB monitors index searches, • R-Trees (MyISAM for spatial and if it notices that it will benefit from a hash index, indexes) InnoDB automatically builds one. (5.1.24 and greater)
  • 16. Does the storage enginereally make a difference? MyISAM Inserts XtraDB Inserts ARCHIVE Inserts User Load Per Second Per Second Per Second 1 3,203.00 2,670.00 3,576.00 4 9,123.00 5,280.00 11,038.00 8 9,361.00 5,044.00 13,202.00 16 8,957.00 4,424.00 13,066.00 32 8,470.00 3,934.00 12,921.00 64 8,382.00 3,541.00 12,571.00 Using mysqlslap, against MariaDB 5.1.55, the ARCHIVE engine has 50% more INSERT throughput compared to MyISAM, and 255% more than XtraDB.
  • 17. MyISAM• Pros? • no transactions • excellent INSERT • no foreign key performance support • small footprint • Typical uses • supports full-text • logging search (FTS) • auditing• Cons? • data warehousing
  • 18. MyISAM II• In my.cnf, remember to • myisam_use_mmap set the key_buffer_size. enables MyISAM to use This is memory*0.40, as memory mapping (7-40% MyISAM uses the OS speed improvement) cache for tables • key_cache_segments = 1• Using DRBD (which enables segmented key requires transactional caches in MariaDB - engine) but still want ~250% improvements, as FTS? Create a FTS it mitigates thread “slave” MyISAM table contention for key cache lock
  • 19. InnoDB• Maintains its own buffer pool (does aggressive memory caching)• Uses tablespaces (several files on disk, raw disk support)• Typically used for OLTP operations
  • 20. InnoDB: Tuning• innodb_file_per_table - • innodb_flush_log_at_trx split InnoDB data into a _commit=1 - logs file per table, rather than flushed to disk at each one contiguous file transaction commit. Guarantees ACID. • allows optimize table `table` to run • innodb_log_file_size - keep it high• innodb_buffer_pool_size (64-512MB), though recovery time increases =(memory*0.8) (largest=4GB)
  • 21. InnoDB: Tuning II• SHOW ENGINE INNODB STATUS;• InnoDB supports both row & statement based replication• Assign a primary key, otherwise InnoDB assigns one for you. Also keep it small - its appended to every record in secondary index
  • 22. XtraDB• InnoDB data dictionary as I_S tables• Enhanced InnoDB data statistics & SHOW ENGINE INNODB STATUS• Lots more... see: software/percona-server/feature- comparison/
  • 23. ARCHIVE• Store large amounts of data without indexes, in small disk footprint• SELECT and INSERT operations only• Good for data audit use• Uses AZIO (zlib) compression
  • 24. FederatedX• Create logical pointers to tables that exist on other MySQL servers; these can then be linked together to form one logical database• A federated table pointing to an InnoDB table on another server, will have transaction support (in 5.1) • Capabilities limited to underlying engine on remote server• CREATE TABLE t1 (...) ENGINE=FEDERATED CONNECTION=mysql://username:pwd@myhost:3306/db_name/ tbl_name• Can also be used for synchronous replication • Federated table on master server pointing to slave; triggers on master table to write all changes to remote table once applied to the master
  • 25. Memory• Previously known as HEAP tables• In-memory engine• Hash index used by default, B-Tree available too• Typical uses? • Lookup tables • Session data • Temporary tables • Calculation tables• Cons? • Server dies, all rows are lost
  • 26. Aria• Based off the 5.1 code • 1.0 – crash-safe MyISAM, with cacheable row format • 1.5 – concurrent INSERT/SELECT • Soon to be merged, then... • 2.0: transactional + ACID compliance • 3.0: high concurrency, online backup• Goal: ACID compliant, MVCC transactional storage engine, based on MyISAM• Target? Data warehousing• Uses big log files (1GB by default)• 8K pages used by default (MyISAM uses 1K pages)
  • 27. PBXT• MVCC, transactional, ACID compliant, foreign key support• row-level locking for updates, so maximum concurrency• immediate notification if client processes are deadlocked• write-once, as it uses a log-based architecture (write data to DB without first writing to transaction log)• support for BLOB streaming with Blob Streaming engine
  • 28. SphinxSE• CREATE TABLE t1 (..) • monitor it - SHOW ENGINE=SPHINX ENGINE SPHINX CONNECTION=”sphin STATUS; x://localhost:9312/test”; • can JOIN a SphinxSE• SELECT * from t1 search table and tables WHERE query=‘test using other engines as it;mode=any’; well • matching modes, • limits, filters, ranges v/about-sphinxse supported
  • 29. Storage Engine API• MySQL_Internals_Custom_Engine• creating-new-storage-engine.html• SHOW PLUGINS;•• storage/example/ and storage/ example/ha_example.h
  • 30. Writing your own• Find the plugin path - show variables like “%plugins%”; +---------------+-----------------------------------+ | Variable_name | Value | +---------------+-----------------------------------+ | plugin_dir | /opt/maria/5.2.6/lib/mysql/plugin | +---------------+-----------------------------------+ • note that this is also where you store UDFs• Copy the relevant engine (eg.• INSTALL PLUGIN myengine SONAME;• Server registers plugin to mysql.plugin table, and now ENGINE=myengine will work
  • 31. Things to think about• Backup is not engine-independent • MyISAM, InnoDB, PBXT • LVM/ZFS snapshots solve this• Different engines have different monitoring options• Mix and match; use summary tables
  • 32. What others are using• Wordpress (blog): uses default engine, MyISAM is fine• MediaWiki (wiki): prefers InnoDB, except for “searchindex” table, which is MyISAM • phase3/maintenance/tables.sql?view=markup• vBulletin (forum): MyISAM• SugarCRM (CRM): MyISAM (with conversion script to InnoDB provided)• Zimbra Collaboration Suite: InnoDB
  • 33. Q&A? email: colin@montyprogram.com | @bytebot / url: