June 19, 2013

Post: Ultimate MySQL variable and status reference list

January 8, 2011 By 4 Comments

… amazing MySQL manual, especially the option and …lock_wait_timeoutblogpercona.commanual locked_in_memoryblogpercona.commanual logblogpercona.commanual …tablesblogpercona.commanual optimizer_prune_levelblogpercona.commanual optimizer_search_depthblogpercona.commanual optimizer_switchblogpercona….

Filed Under: Insight for DBAs, MySQL

Post: Distributed Set Processing with Shard-Query

May 14, 2011 By 27 Comments

…. Every SQL statements breaks down into a relational algebra equation. In Algebra you …speaks SQL, but right now only MySQL storage nodes are supported. Amdahl’…OPTIMIZATIONS: * Base level table name: `aggregation_tmp#74082863` * IN list optimization enabled * Detected an IN list with 2 items * IN…

Filed Under: MySQL

Post: MySQL Upgrade Webinar Questions Followup

June 28, 2012 By 7 Comments

… significant development since MySQL 4.1, so in-place upgrade of MySQL 5.0 to MySQL 5.5 … statements? Yes. This is exactly how it is done in many cases. There is really no gain in…TABLE) or disabling some of the optimization/statistics related features in new version. Innodb statistics can especially …

Filed Under: Insight for DBAs, MySQL

Post: Be productive with the MySQL command line

December 21, 2012 By 14 Comments

… mysql> pager Default pager wasn’t set, using stdout. Using edit When you try to optimize …to write documentation or when you are in the middle of an emergency, you …statements you typed and their output, pretty much like the Unix tee command: mysql> tee queries.log Logging to file ‘queries.log’ mysql…

Filed Under: Insight for DBAs, MySQL

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

February 26, 2013 By 1 Comment

…, however, MySQL apparently has no problem with either of the following statements: mysql> insert into …optimize_start_time | | | optimize_end_time | | | stopword_table_name | | | use_stopword | 1 | | table_state | 0 | +—————————+———+ 10 rows in set (0.02 sec) mysql> optimize…

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

Post: MySQL Users Conference - Innodb

May 9, 2007 By 6 Comments

… bunch of others due to statement level MySQL Replication which among other requirements, needs all auto-increment values in multiple value insert to… full statement duration. The problem with multi value inserts however is the following – even if you know number of values in insert statement… optimized on systems with 1-2 SATA drives so they are far from optimal for server grade IO subsystems. These are for MySQL…

Filed Under: Events and Announcements Tagged With:

Post: MySQL EXPLAIN limits and errors.

July 24, 2006 By 6 Comments

… tables (selects in FROM clause) are used. MySQL will execute these subselects on explain to provide plan for top most statement, so if you made an error in select in from… is also not used in optimization which may produce suboptimal plans if stored functions are used in queries. In general in my opinion EXPLAIN needs…

Filed Under: Insight for Developers Tagged With: ,

Post: New SpecJAppServer results at MySQL and Sun.

November 12, 2008 By Leave a Comment

… an Prepared Statements can be more efficient on the server side but I guess something is not as well optimized with them as it could be which makes it better to disable them. The MySQL Settings are probably what is the most interesting: MySQL 5.0 Tuning in /etc/my.cnf (included in FDA) [mysqld…

Filed Under: Benchmarks

Post: MySQL Query Cache

July 27, 2006 By 70 Comments

… helpful for MySQL Performance optimization tasks but there are number of things you need to know. First let me clarify what MySQL Query…” it proceeds with query lookup in cache if not – skips it. Does not support prepared statements and cursors Query Cache works with query text and want full result set at once. In prepared statements there is…

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Post: 10+ Ways to Crash or Overload MySQL

November 13, 2007 By 20 Comments

… by single prepared statement you can create statement with thousands of placeholders and send data for each of them using mysql_stmt_send_long_data call – Server buffers such data until you have executed prepared statement. Innodb Table Cache…_packet. However some MySQL optimizations such as equity propagation and range expansion can cause Parse Tree to blow up in size. For most…

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