June 18, 2013

Post: How Percona does a MySQL Performance Audit

November 24, 2008 By 17 Comments

…query, I run EXPLAIN if possible (rewriting non-SELECT queries if needed, and using careful judgment for queries with subqueries in…

Filed Under: Insight for Developers Tagged With:

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

March 4, 2013 By 7 Comments

…in MySQL 5.6: Part 2, The Queries![/caption] This is part 2 in a 3 part series. In… There’s only one row in the table that actually matches all three search terms, and in this case, …single phrase: With 5.5: mysql: SELECT id, full_name, MATCH(full_name, details) AGAINST (‘”Thomas B Smith”‘ IN…

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

Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark

March 11, 2013 By 7 Comments

…queries in this post, but instead intended to focus only on the overall response time for answering all of the queries in…tables in the other direction mysql> select…

Filed Under: MySQL Tagged With: , , , , ,

Post: Using any general purpose computer as a special purpose SIMD computer

May 16, 2011 By 5 Comments

…, 0.0063340663909912s) The set of three numbers are wall clock time …in the table. This allows MySQL to set up a sequential scan over the items in…queries together. This query is single threaded, and thus this serves no purpose. It will be much more important in a moment. — AGGREGATION SQL: SELECT…

Filed Under: MySQL

Post: Faster MySQL failover with SELECT mirroring

February 1, 2009 By 9 Comments

…in both directions. Aside from MySQL …than a single server can …in the buffer pool. I measured the active master’s buffer pool with the following query: select table_schema, table…three samples stored in tables on my laptop, I wrote a query against these three sets of stats to find the top tables…

Filed Under: Insight for DBAs Tagged With: , ,

Post: How to recover deleted rows from an InnoDB Tablespace

February 20, 2012 By 4 Comments

…three of them: A) INNODB_SYS_INDEXES Percona Server has some extra tables in INFORMATION_SCHEMA that can help us to find the different indexes and types. mysql (information_schema) > select…

Filed Under: Insight for DBAs, MySQL

Post: Full Text Search Webinar Questions Followup

August 24, 2012 By 5 Comments

…of any SQL query, and if you can form a SELECT query that returns the “…table-scans. Jessy B. also asked: Q: Were these tests performed on a single… me two to three weeks to do something equivalent with MySQL and it … solutions had in common, so I tested only simple queries without customizing the …

Filed Under: Events and Announcements, Insight for Developers, MySQL

Post: Why MySQL could be slow with large tables ?

June 9, 2006 By 141 Comments

…selects about 1% of the table. The times for full table scan vs range scan by index: mysql> select…In MySQL single query runs as single thread (with exeption of MySQL Cluster) and MySQL issues IO requests one by one for query execution, which means if single query…

Filed Under: Insight for DBAs Tagged With: ,

Post: High-Performance Click Analysis with MySQL

December 22, 2008 By 13 Comments

…single one doesn’t know what data should live in… wrote a three-part …tables is hard work for the database server.  If you do it on the master with INSERT..SELECT queries…tables in a complex query with many joins. I have never seen this approach scale well. Use The Best Technologies You Can MySQL…

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

Post: On Character Sets and Disappearing Tables

June 21, 2012 By 1 Comment

…table in place.  The first table certainly proceeds well enough: (root@localhost) [oops4]> set foreign_key_checks=0; Query…tables; +—————–+ | Tables_in_oops4 | +—————–+ | dos1 | | dos3 | +—————–+ 2 rows in set (0.00 sec) “Oops” indeed. Where we once had three tables…

Filed Under: Insight for DBAs, MySQL
« Older Posts