June 18, 2013

Post: MySQL Query Patterns, Optimized - Webinar questions followup

June 3, 2013 By 2 Comments

…SQL can produce an infinite variety of  queries.  The query optimizer analyzes queries for common patterns the MySQL… primary key solution for random selection only work when the… random number generator picks values in that range with… you have a dataset that changes infrequently, then this might be…

Filed Under: Insight for Developers, MySQL, MySQL Webinars Tagged With: , , ,

Post: MySQL 5.5 and MySQL 5.6 default variable values differences

February 21, 2013 By 8 Comments

… the values from MySQL 5.5.30 and MySQL 5.6.10 to the different tables and ran the query: mysql [localhost] {msandbox} (test) > select var55.variable_name,left(var55.variable_value,40) value55, left(var56.variable_value,40) var56 from… someone tries to enable it. sql_mode has NO_ENGINE_SUBSTITUTION value by default which is good change as trying to create Innodb…

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

Post: Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit

November 24, 2011 By 2 Comments

…the counter values slightly …select_result*, unsigned long) (sql_select.cc:269) ==9090==    by 0x63A3E3: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:5179) ==9090==    by 0x6435EA: mysql…changes that might make the issues not-so-minor. Additionally, I’d consider backporting and using MySQL…

Filed Under: MySQL

Post: MySQL: Followup on UNION for query optimization, Query profiling

August 14, 2006 By 14 Comments

…have to use the union. So changing query to: mysql> SELECT sql_no_cache name FROM people WHERE…rows in set (0.39 sec) mysql> show status like “Handler%”; +—————————-+——-+ | Variable_name | Value | +—————————-+——-+ | Handler_commit | 0 | | Handler_delete | 0…

Filed Under: Insight for Developers Tagged With: ,

Post: Flexviews - part 3 - improving query performance using materialized views

April 4, 2011 By 20 Comments

…values…changes past the transaction id to which you have computed them. And then confirm they contain the same results mysql> select…

Filed Under: Insight for DBAs, MySQL

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

November 1, 2012 By 1 Comment

… (`id`, `guest_language`, `guest_country`, `score`) VALUES (NEW.`id`, NEW.`guest_language`, …_country` = ? AND `score` <= ?) ) /*pt-online-schema-change 10451 copy nibble*/ SELECT /*!40001 SQL_NO_CACHE */ `guest_country`, `guest… the tool, problems with the MySQL server (privileges, etc.), or other …

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

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

February 26, 2013 By 1 Comment

…mysql> set global innodb_optimize_fulltext_only=1; mysql> select * from information_schema.innodb_ft_config; +—————————+——–+ | KEY | VALUE…change to the default InnoDB settings for MySQL 5.6, and that was to change…

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

Post: Distributed Set Processing with Shard-Query

May 14, 2011 By 27 Comments

…table and thus the logic for applying changes via ON DUPLICATE KEY UPDATE is the…of compute resource which speaks SQL, but right now only MySQL storage nodes are supported. … flight_delayed` + VALUES(`sum(DepDelay >= 0) flight_delayed`) — SQL TO SEND TO SHARDS Array ( [0] => SELECT origin_airport_…

Filed Under: MySQL

Post: MySQL Query Cache

July 27, 2006 By 70 Comments

…there is query with placeholders and additional parameter values which would need extra care – it is not …and use only SQL_CACHE hint for queries which you want to have cached – such as SELECT SQL_CACHE col…? Third party application – You can’t change how it works with MySQL to add caching but you can…

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Post: Shard-Query EC2 images available

May 11, 2011 By 2 Comments

… instances. MySQL will fail to start on a micro instance, simply decrease the values …selected in the list of columns to show (click show/hide to change the columns) That the “public dns” field is selected… cd shard-query/ $ ./run_query < queries.sql | tee raw |./pivot_results & [1] 12359 $ tail -…

Filed Under: MySQL
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