June 19, 2013

Post: Join Optimizations in MySQL 5.6 and MariaDB 5.5

April 4, 2012 By 4 Comments

…MySQL can employ many other optimizations like for example if columns other then the secondary key columns…changed to become sequential. The two other most important numbers are values for Innodb_buffer_pool_reads and Innodb_data… run tests to see what specific types of queries would benefit from Hash…

Filed Under: Benchmarks, Insight for DBAs, MySQL Tagged With: , , , , , , , , , , , , , ,

Post: Knowing what pt-online-schema-change will do

November 1, 2012 By 1 Comment

… –dry-run and –print, pt-online-schema-change changes nothing but prints a lot of information…never knows. Are the columns used correctly given their data types and definitions?  If a column is defined as “…bugs in the tool, problems with the MySQL server (privileges, etc.), or other oddities, there…

Filed Under: Insight for DBAs, Percona Software Tagged With:

Post: Hijacking Innodb Foreign Keys

January 2, 2012 By 2 Comments

… not change “parent_id” column you can update data just fine, however if you want to change the parent_id column, even if you change it… satisfy foreign key conditions (have column child table is referencing and have it of proper type and indexed): mysql> set foreign_key_checks…

Filed Under: Insight for DBAs, MySQL

Post: Ultimate MySQL variable and status reference list

January 8, 2011 By 4 Comments

…MySQL …_show_column_typesblogpercona….change_bufferingblogpercona.commanual innodb_checksumsblogpercona.commanual innodb_commit_concurrencyblogpercona.commanual innodb_concurrency_ticketsblogpercona.commanual innodb_data_file_pathblogpercona.commanual Innodb_data… slave_type_conversionsblogpercona…

Filed Under: Insight for DBAs, MySQL

Post: Data compression in InnoDB for text and blob fields

May 30, 2012 By 2 Comments

… certain types of columns in a table while leaving other columns uncompressed…any query or application logic changes so we chose to …MySQL manual states: This setting may still be useful for tables with many long BLOB, VARCHAR or TEXT columns… them new and migrate data, or affect existing tables with…

Filed Under: Insight for DBAs, Insight for Developers, MySQL, Percona Software

Post: When is MIN(DATE) != MIN(DATE) ?

September 4, 2012 By 5 Comments

… INDEX `uid` (uid, update_time), INDEX `bar` (some_other_columns) …. ) ENGINE=InnoDB; When he ran this query: … The documentation for MySQL 5.5 states that the supported range for the DATETIME type is 1000-01… the other hand, it hasn’t actually changed any data in those DATETIME values, and now it’s…

Filed Under: Insight for DBAs, Insight for Developers, MySQL

Post: MySQL-Memcached or NOSQL Tokyo Tyrant - part 3

October 19, 2009 By 25 Comments

…MySQL and Memcached, and later on other NoSQL solutions.  Tokyo actually allows you to use several types… clause and search individual columns, and a ton more “database…better off not storing my data in MySQL and instead looking …, and data size increases how does performance differ or change?  One …

Filed Under: Benchmarks, Cloud and NoSQL, MySQL Tagged With: , ,

Post: MySQL Prepared Statements

August 2, 2006 By 21 Comments

…best performance in your application using MySQL you should learn about prepared statements… is pretty expensive especially for certain data types. Furthermore BLOBs require escaping as …data so query changes it meaning. You also can bind direct variables to return columns – which means not only data…

Filed Under: Benchmarks, Insight for Developers Tagged With:

Post: ANALYZE: MyISAM vs Innodb

September 3, 2008 By 9 Comments

…you can allow more data change while your index stats…values change: mysql> analyze table antest_innodb; +——————–+———+———-+———-+ | Table | Op | Msg_type | Msg_text | …column “c” to NULL in both tables and see how values change: mysql…

Filed Under: Insight for DBAs Tagged With: ,

Post: InnoDB Full-text Search in MySQL 5.6 (part 1)

February 26, 2013 By 1 Comment

…changed. NOTE 2: For purposes of this discussion, I used two separate data…column, however, MySQL apparently has no problem with either of the following statements: mysql… mysql> optimize table dir_test_innodb; +———————-+———-+———-+———-+ | Table | Op | Msg_type | Msg_…

Filed Under: Insight for DBAs, Insight for Developers, MySQL Tagged With: , , , , ,
« Older Posts
Newer Posts »