MySQL DBA Training 1 MySQL Architecture HD

Session 1: MySQL Architecture. To Learn or Teach Linux visit www.theskillpedia.com, A Marketplace for Learners and Trainers. www.hometutor.net.in. To know about me visit my profile at www.rnsangwan.com. I deliver online training on Business Analysis, Linux, Unix, MySQL, Sybase, SQL Server, Perl, Python, R Data Analysis, Scala etc. http://youtube.com/user/theskillpedia General RDBMS Architecture • It has three main components: • Application Layer • Logical Layer • Physical Layer MySQL Architecture Overview APPLICATION LAYER • Users and clients interacts with the MySQL RDBMS. • Three components: ◦ Administrators ◦ Clients ◦ Query Users • Query users interact with MySQL RDBMS using “mysql”. MySQL Architecture Overview LOGICAL LAYER • The logical layer of MySQL architecture is divided into various subsystems. ◦ Query Processor. ◦ Transaction Management. ◦ Recovery Management. ◦ Storage Management. • These sub systems work together to process the requests issued to the MySQL database server. Physical Layer Physical Layer • Data files, which store the user data in the database • Data dictionary, which stores metadata about the structure of the database Physical Layer  Database directories. Each database corresponds to a single directory.  Table format files (.frm files) that contain a description of table structure.  The InnoDB storage engine has its own tablespace and log files.  The default tablespace file is named ibdata1 and the default log files are named ib_logfile0 and ib_logfile1.  Server log files and status files. Physical Layer  A storage engine has a particular set of operational characteristics.  When you create a table, you can choose what storage engine to use. MySQL’s Logical Architecture ◦ Embedded DML Pre-compiler. ◦ DDL Compiler. ◦ Query Parser. ◦ Query Preprocessor. ◦ Security/Integration Manager. ◦ Query Optimizer. ◦ Execution Engine. • The output of one of the above component becomes the input for another. • Query processor layer is scalable and evolvable. Transaction Management • It facilitates concurrent data access. • Provides locking facility. • Ensures multiple users/sessions access data simultaneously in a consistent way. • Prevents data corruption or data damage. • Lock Manager is the sub component name that handles locking. Recovery Management • Log Manager ◦ Logs every operation executed in the database. ◦ Stores the operations logs as MySQL Commands. • Recovery Manager ◦ Responsible for recovering the database to its last stable state. ◦ Uses the logs created by the log manager. Memory Management • Buffer Manager ◦ It allocated memory resources. • Resource Manager ◦ Accepts the requests from execution engine. ◦ Requests the details from buffer manager. ◦ It actually receives references of data with memory from buffer manager. ◦ Returns this data to the upper layer. MySQL Concepts: InnoDB  It supports row-level locking.  Foreign key referential-integrity constraint c