June 18, 2013

Post: MySQL Query Patterns, Optimized - Webinar questions followup

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…

Post: MySQL 5.5 and MySQL 5.6 default variable values differences

… 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…

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

…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: mysqlchanges that might make the issues not-so-minor. Additionally, I’d consider backporting and using MySQL

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

…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…

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

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

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

… (`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 …

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

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

Post: Distributed Set Processing with Shard-Query

…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_…

Post: MySQL Query Cache

…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…

Post: Shard-Query EC2 images available

… instances. MySQL will fail to start on a micro instance, simply decrease the valuesselected 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 -…