I would love to know the answer to this as well. I know there are a number of functions of mysqlcheck... -c to check for corruption.. and ensure nothing needs to be repaired -o to Optimize, which is kind of like defragmenting, removing deleted rows.. and this may be the one that is causing the 100% duplication & downtime.. -r for repair what -c found, or if there was some unanticipated downtime.
I'm trying to determine what the best practices is with MySQL databases. As an Oracle DBA, I run stats fairly often for the CBO, but that doesn't look like the same thing that -o does. I'm guessing that for a medium-usage database, I'd use -o during a specified downtime, perhaps accompanying the upgrade, whether it is monthly or whichever, but run -c more often to check for corruption. Does anyone have any documentation or knowledge of best practices, especially for version 5.6? ~ Tyfanie Wineriter ~ Database Administrator University of Oregon 1212 University of Oregon Eugene, OR 97402-1212 (541) 346-1366 -----Original Message----- From: Lukas Lehner [mailto:webleh...@gmail.com] Sent: Wednesday, June 11, 2014 6:38 AM To: mysql Subject: mysqlcheck downtime > 30 minutes for Java web application Hi I read in "MySQL, Fifth Edition" by Paul DuBois that we should do a regular mysqlcheck. We have all InnoDB tables. As far as I unterstand the tables get read and write locked during mysqlcheck. The database will grow 100x in size, at the moment only initial load. It means big downtime. $ time mysqlcheck --all-databases [...] real 29m41.449s user 0m0.019s sys 0m0.015s mysql> SELECT table_schema "Data Base Name", SUM( data_length + index_length) / 1024 / 1024 -> "Data Base Size in MB" FROM information_schema.TABLES GROUP BY table_schema ; +--------------------+----------------------+ | Data Base Name | Data Base Size in MB | +--------------------+----------------------+ | imzweffefr | 38420.97170544 | | information_schema | 0.00781250 | | mysql | 0.63046169 | +--------------------+----------------------+ 3 rows in set (5.86 sec) You all do mysqlcheck? Is it really mandatory? What's the risk if I don't do it regularly? -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql
