Learn Database Design with MySQL - Chapter 3 - My sql storage engines
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Storage engines are what MySQL uses to store, handle, and retrieve data from database tables. The two most popular storage engines are MyISAM and InnoDB. MyISAM was the default until MySQL 5.5.5, when InnoDB became the default. You can select a specific storage engine for a database or individual tables. Reasons to choose a certain storage engine include the amount of data, speed/performance, functionality, and data integrity.
Learn Database Design with MySQL - Chapter 3 - My sql storage engines
- 1. DATABASE DESIGN USING MYSQL Understanding Storage Engines
- 2. WHAT IS A STORAGE ENGINE? A storage engine is what MySQL uses to store, handle and retrieve data from a database table. There are 10 storage engines in MySQL but all of them may not be available in certain situations. The most popular are MyISAM and InnoDB. MyISAM was the default storage engine until MySQL 5.5.5 was released. Now InnoDB is the default. mysql> show engines will show you a list of supported engines
- 3. STANDARD STORAGE ENGINES • MyISAM • InnoDB • MERGE • MEMORY (HEAP) • BDB (BerkeleyDB) • EXAMPLE • ARCHIVE • CSV • BLACKHOLE • ISAM
- 4. STORAGE ENGINE BENEFITS Some of the reasons that you may want to use a certain storage engine • Amount of data • Speed & Performance • Functionality • Max number of rows • Data Integrity
- 5. WHEN AND WHERE TO CHOOSE You can select a specific storage engine for a database as well as individual tables CREATE TABLE table1 (i INT) ENGINE = INNODB; CREATE TABLE table2 (i INT) ENGINE = CSV; You can set the default storage engine to be used during the current session by setting the “default_storage_engine” variable: SET default_storage_engine=MYISAM;
- 6. MYISAM STORAGE ENGINE MyISAM is based on the older (and no longer available) ISAM storage engine but has many useful extensions & features MyISAM supports Full Text Search Indexes Data Caches – No Index Caches – Yes Uses Table-Level Locking MyISAM type is great for sites that have a very low INSERT/UPDATE rate and a very high SELECT rate
- 7. INNODB STORAGE ENGINE InnoDB offers a lot more features than MyISAM that increases performance. Uses row-Level Locking which has better performance than table-level locking InnoDB allows parallel INSERT/UPDATE/DELETE queries to be ran on the same table, unlike MyISAM where each query has to wait its turn to run. InnoDB supports foreign key functionality which is a huge advantage
- 8. OTHER STORAGE ENGINES • MERGE - Enables users to have a collection of identical MyISAM tables to be handled by a single table. • MEMORY(HEAP) – Provides in-memory tables. Not great for long term usage • BDB(Berkeley) - Handles transaction-safe tables and uses a hash based storage system. There are many downfalls to the BDB system, including the speed on un-index rows, and this makes the BDB engine a less than perfect engine choice
- 9. OTHER STORAGE ENGINES • EXAMPLE - It is a "stub" engine that serves no real purpose, except to programmers. EXAMPLE provides the ability to create tables, but no information can be inserted or retrieved. • ARCHIVE – Used for very large amounts of data. Only supports SELECT and INSERT. Great for logs. • CSV - Stores data in text files using comma-separated values. Great for transferring data to a spreadsheet for later use. • BLACKHOLE – Doesn’t store actual data. Good for testing database structure, indexes and queries
- 10. THAT’S IT!