June 18, 2013

Post: The small improvements of MySQL 5.6: Duplicate Index Detection

May 31, 2013 By Leave a Comment

…in detail what the “will be disallowed in a future release” means. In MySQL 5.7 the checks will be stricter: in…. What is the difference? Let’s see an example. If we execute: mysql> ALTER TABLE test ADD INDEX (col2… the first one. Why can’t MySQL enforce this kind of constraints? For many reasons: the…

Filed Under: Insight for DBAs, MySQL, On Ground Training, Percona Toolkit, Training Tagged With: , , , , , , , , ,

Post: MySQL Query Patterns, Optimized - Webinar questions followup

June 3, 2013 By 2 Comments

… keywords were returned in a different order from what you specify in the query? The tuple comparison you’re referring to is this example… each kind_id. It was more efficient in this case to force MySQL to scan the `title` table first, grouping by kind_id in index order.  This made the first table in…

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

Post: Advanced index analysis with mk-index-usage

November 11, 2010 By 2 Comments

… results in my MySQL sandbox instance. The new option is –save-results-database. The full mk-index-usage command looks like this: mk-index-usage… time it uses one index, and the rest of the time it uses another. These kinds of variations in query execution plans are… looking here, but we know that there is something worth looking into. What is query 7675136724153707161, anyway? mysql> select * from queries where query_id…

Filed Under: Insight for DBAs, MySQL

Post: What to tune in MySQL Server after installation

September 29, 2006 By 118 Comments

…as MySQL DBAs or be involved with MySQL Performance in some way is to ask them what should be tuned in MySQL …larger than indexes in many cases. Check however if all of key_buffer is used over time – it is … innodb_log_buffer_size Default for this one is kind of OK for many workloads with medium …

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Post: Is there room for more MySQL IO Optimization?

January 3, 2013 By 11 Comments

…in set (0.02 sec) The table is approximately 30GB in size including indexes which is…in buffered mode. Take a look at the graph: What this tells me is there is a lot of untapped potential in MySQL…

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

Post: InnoDB Full-text Search in MySQL 5.6: Part 2, The Queries!

March 4, 2013 By 7 Comments

…-text Search in MySQL 5.6: Part 2, The Queries![/caption] This is part 2 in a 3 part series. In part 1,… our FT index on the InnoDB table and try the above queries one more time. We already know what the…of InnoDB FTS compare to its MyISAM counterpart, and what kinds of tricks can we use to make it go…

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

Post: Troubleshooting MySQL Memory Usage

March 21, 2012 By 5 Comments

… is being used by current MEMORY tables: mysql> select sum(data_length+index_…many kinds of memory leaks and I would say these are rather rare in MySQL…MySQL, MariaDB or Drizzle bring improvements in this space allowing us to see directly for what purpose memory is allocated and so detect all kinds…

Filed Under: Insight for DBAs, MySQL

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

February 26, 2013 By 1 Comment

…is true that InnoDB full-text search in MySQL 5.6 (part 1) in MySQL 5.6 is syntactically identical to MyISAM full-text search, in…that kind of behavior unsettling. I don’t like case-sensitivity in my…What, exactly, are they? In short, the _CONFIG.ibd file contains configuration info about the FT index…

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

Post: Percona Live MySQL Conference and Expo 2013: The talks I want to see

February 12, 2013 By 4 Comments

…Innodb supports Full-text indexing, I’m interested in other good discussion …in MySQL 5.6 - (Vadim Tkachenko, Percona) – Tuning Innodb is a huge part of my job, and getting up to 5.6 is…in the latest/greatest out of Tungsten, and also what decision points he tends to bring to the table with this kind…

Filed Under: Events and Announcements, MySQL, Percona Live Tagged With: , ,

Post: Innodb vs MySQL index counts

November 29, 2011 By 6 Comments

… of SHOW CREATE TABLE to what Innodb thinks.  What Innodb thinks is in the Innodb Data dictionary. The …INDEXES table, which exists in Percona Server 5.1, but doesn’t appear in MySQL until 5.6 (if the manual is…index to it, and copy the new .frm back over the original.  Kind of scary. My advice is …

Filed Under: MySQL
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