… learn about MySQL Performance Optimization is to avoid using functions when comparing constants or order…closer look to WHERE clause you will find the reason – date(d) equals to date(now()) which …WHERE clause. If course it works for direct constants as well. However if functions are different MySQL…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 12 Comments
…where. You may not use sub-queries or any non-deterministic functions like NOW() or RAND(). HAVING clauses, ORDER BY clauses… order lines. Refreshed both views. Compared the refresh performance and query results…they are out-of-date and must be refreshed: mysql> select sum(total_lines) from complete…
Post: SELECT UNION Results INTO OUTFILE
September 14, 2011 By Leave a Comment
… point. When doing SELECT … UNION SELECT, where do you put the the INTO OUTFILE clause? On the first SELECT, on the last… set (0.00 sec) Compared to using UNION simply: mysql [localhost] {msandbox} (employees) > EXPLAIN SELECT * -> FROM employees -> WHERE hire_date BETWEEN ’1990-01-01…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
…MySQL does have its limitations, it reports only a subset of stats, however if you compare… 26.23M rss, 62.49M vsz # Current date: Thu Dec 29 07:09:32 2011 … option_name, option_value FROM wp_options WHERE autoload = ‘yes’\G This is the … the query, by using a LIMIT clause or by filtering based on the …
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…off with these commands: date uname -a cat /etc…where there’s a /var/lib/mysql and an /etc/my.cnf, and the server is installed in /customsoftware/mysql… I find something, I compare it against the server…clause, which will actually execute the inner subquery!), and examine the query plan. This is where…
Post: PBXT benchmarks
April 8, 2007 By 14 Comments
…password` varchar(64) NOT NULL default ”, `dob` date default NULL, `address` varchar(128) NOT NULL…KB 4GB of RAM MySQL version We used MySQL 5.1.16-beta sources… clause. READ_KEY_POINT_NO_DATA Query: SELECT state_id FROM $tableName WHERE …such results. The one problem comparing to InnoDB is the access…
Post: InnoDB vs MyISAM vs Falcon benchmarks - part 1
January 8, 2007 By 117 Comments
…NOT NULL default ”, `dob` date default NULL, `address`…LIMIT clause, …MySQL 5.1.14-beta sources for MyISAM / InnoDB and MySQL 5.1.14-falcon bitkeeper tree bk://mysql.bkbits.net/mysql…WHERE id = %d Simple but very quick query to retrieve value from PK. The results for InnoDB and MyISAM are comparable…
