…InnoDB DEFAULT CHARSET=latin1 COMMENT=’Contains all avaialble data from 1988 to 2010′; mysql> use ontime1; Database changed mysql> show table status like…run_query script will run one more more semicolon terminated SQL statements. The queries for the benchmark are in ~ec2-user/shard-query/queries.sql…
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
…phone, n_name, c_address, c_comment order by revenue desc LIMIT 20; In-memory workload Now let’s …not in MySQL 5.6, is that because of a bug in MySQL 5.6 code? As MRR was used in both MySQL … correct query execution plan is not used, there is no difference in query times between MySQL 5.5 and MySQL 5….
Post: A micro-benchmark of stored routines in MySQL
August 16, 2009 By 7 Comments
… execution plan. You should never use IN() subqueries the way I do, at least not in MySQL 5.1 and earlier. I loaded the World sample database and cooked up this query: select sql_no… subquery badly in the first query! (If you think of a better way to compare apples and uhm, apples… please comment). The poorly…
Post: Database problems in MySQL/PHP Applications
August 11, 2006 By 13 Comments
… cause mixed feellings so I decided it is worth commenting: 1. Using mysql_* functions directly This is probably bad but I do… other hand in MySQL you might be better of using several queries than doing complicated ones. Of course you would rather use IN() than do 100 of queries in this case. This most applies to subqueries Where Subselects with IN() become corellated even…
Post: Moving Subtrees in Closure Table Hierarchies
February 14, 2011 By 18 Comments
… comments, personnel org charts, or nested bill-of-materials. Sometimes it’s tricky to do this in SQL and still run efficient queries… storing and querying trees in an SQL database, including the design I call Closure Table. In Closure Table, we store every path in a… update in FROM clause.” We can’t DELETE and SELECT from the same table in a single query in MySQL. But we can use MySQL‘s…
Post: Is your MySQL Application having Busy IO by Oracle Measures ?
January 8, 2012 By 1 Comment
…MySQL Users are running applications of these scale, for single MySQL Server ? Please comment…MySQL we often start “sharding” or splitting data other way because operationally working with large table and data sizes in MySQL…
Post: Is there room for more MySQL IO Optimization?
January 3, 2013 By 11 Comments
…NULL Create_options: Comment: 1 row in set (0.02 sec) The table is approximately 30GB in size including indexes … to large full table scan and index scan queries, though this is really not the point. The …_Ahead which is not available in MySQL 5.5 (different version is added back in MySQL 5.6) so I …
Post: Percona Live MySQL Conference and Expo 2013: The talks I want to see
February 12, 2013 By 4 Comments
… probably end up in Galera Cluster Best Practices, though I’ve heard that talk from Seppo (Codership) before. MySQL Query Anti-Patterns that… about new Xtrabackup feature sets. Internals of new InnoDB features in MySQL 5.6 - (Vadim Tkachenko, Percona) – Tuning Innodb is a huge… like to attend at the conference and why? Best answer in the comments below wins the pass. Include a link to the…
Post: MySQL Configuration Wizard Updated
January 26, 2012 By 5 Comments
…MySQL behaviors. These are the kinds of things that Drizzle fixes — and should be fixed by default in MySQL… visual EXPLAIN tool, a configuration advisor, a query analysis tool, a way to register …in the comments. We hope this suite of free browser-based tools helps you become a more productive MySQL…
Post: MySQL VIEW as performance troublemaker
August 12, 2007 By 57 Comments
… which appeared in MySQL 5.0 and quite frequently VIEWs are used to help in writing the queries – to keep queries simple without … comments table which holds users comments to the blog, naturally containing user_id which left comment, comment_id and comment text: CREATE TABLE `comments` ( `…
