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MySql cheat sheet
This document provides a summary of tools and commands for monitoring, administering and optimizing a MySQL database. It describes utilities like mytop and innotop for live monitoring of MySQL, commands for checking status, lists of databases/tables/columns, and how to view and change configuration parameters. Methods for remote data dumps/imports, importing CSV files, and handling query output are also outlined.
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MySql cheat sheet
- 1. MySQLCheatSheet MySQLisanopen-sourcerelationaldatabasemanagementsystem(RDBMS). bylam LiveMonitoringof MySQL Therearetwousefultools: mytop innotop with"mytop"beinganown Debianpackage,while "innotop"isincludedinthe "mysql-client"package. Frombothinnotophasthe moreadvancedfunctionality. Bothneedtobecalledwith credentialstoconnecttothe database: mytop -u <user>-p<pas sword> innotop -u <user> -p<p assword> ShowMySQLStatus Youcangetaverysimple statusbyjustentering"s"in the"mysql"commandline clientprompt: mysql> s Youcanshowthereplication statususing SHOW SLAVE STATUS G SHOW MASTER STATUS G Notethatthe"G"insteadof ";"justmakestheoutputmore readable.Ifyouhave configuredslavestoreport namesyoucanlistthemon themasterwith: SHOW SLAVE HOSTS; CheckInnoDBstatus show /*!50000 ENGINE */ INNODB STATUS; List Databases/Tables/C olums Youcaneitherusethe "mysqlshow"tool: mysqlshow # List all d atabases mysqlshow <database> # List all t ables of the given data base mysqlshow <database> <t able> # List all c olumns of the given tab le in the given DB Andyoucanalsodoitusing queries: SHOW DATABASES; USE <database>; SHOW TABLES; DESCRIBE <table>; CheckandChange LiveConfiguration Parameters Notethatyoucannotchange allexistingparameters. Somelike innodb_pool_bufferrequirea DBrestart. show variables; # L ist all configuration settings show variables like 'k ey_buffer_size'; # L ist a specific paramet er set global key_buffer_ size=100000000; # S et a specific paramete r MySQLParameter Optimization YoucancheckMySQL parametersofarunning instanceusingtoolslike MySQLTuner MySQLTuning-Primer pt-variable-advisor Alsohavealookatthis MySQLconfigparameter explanation. RemoteMySQL DumpandImport Thefollowingcommand allowsdumpingadatabase fromonesourcehostthat doesn'tseethetargethost whenexecutedonathirdhost thatcanaccessboth.Ifboth hostscanseeeachotherand onehasSSHaccesstothe ImportaCSVfileinto MySQL LOAD DATA IN '<CSV fil ename>' INTO TABLE <ta
- 2. CheatSheetMaker.com SimpleCheatSheet.com # Finallyensure to ed it my.cnf to make the change persistent otheryoucansimplydropone ofthesshcalls. ssh <user@source host> "mysqldump --single-tra nsaction -u root --pass word=<DB root pwd> <DB name>" | ssh <user@targ et host> "mysql -u roo t --password=<DB root p wd> <DB name>" ble name> FIELDS TERMI NATED BY ',' (<name o f column #1>,<<name o f column #2>,<...>); MySQLPager- OutputHandling Using"PAGER"orPyoucan controloutputhandling. Insteadofhaving10klines scrollingbyyoucanwrite everythingtoafileoruse "less"toscrollthroughitfor example.Touselessissue pager less Pageoutputintoascript pager /home/joe/myscrip t.sh OrifyouhavePercona installedgetatree-like "EXPLAIN"outputwith pager mk-visual-explain andthenrunthe"EXPLAIN" query.