… a while. Before joining Percona, Morgan worked as a Technical Instructor for MySQL (and then Sun Microsystems) in Canada where he taught courses…’s as a DBA, System Administrator, and all around techie. Before joining Percona, Matt worked at MySQL and Sun Microsystems as a…
Post: Percona welcomes Ewen Fortune and Piotr Biel
October 1, 2008 By 5 Comments
… with us for quite a few months. Ewen Fortune joins us from Spain, where he lives with his family. Ewen is actually… Spanish, of course. Ewen has been a consultant and contractor before joining Percona, and has many years of experience in Oracle, MySQL…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 23 Comments
…) t JOIN (SELECT Carrier, count(*) AS c2 from ontime_fact join dim_date using(date_id) join dim_flight using(flight_id) WHERE Year…. Infobright was, however, given the chance to review this document before publication, as a courtesy. All findings are represented truthfully, transparently…
Post: MySQL 5.6 vs MySQL 5.5 and the Star Schema Benchmark
March 11, 2013 By 7 Comments
… tuning options which must be investigated (MRR, BKA, ICP, etc) before coming to further conclusions. These will be the topic of…_datekey join customer on lo_custkey = c_customerkey join supplier on lo_suppkey = s_suppkey join part on lo_partkey = p_partkey where c…_datekey join customer on lo_custkey = c_customerkey join supplier on lo_suppkey = s_suppkey join part on lo_partkey = p_partkey where c…
Post: EXPLAIN EXTENDED can tell you all kinds of interesting things
June 15, 2010 By 7 Comments
…select ’0′ AS `c1` from `test`.`j1` join `test`.`j2` join `test`.`j3` where 0 | +——-+——+——————————————————————————-+ 1 row in set…values before completely formulating the plan. You will notice the MySQL replaces the WHERE clause with ‘where …
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
… tables. Q: in trick #1 will “WHERE a IN (2-4)” be worse then “WHERE a IN (2,3,4)”? Another word… lot of performance gains before I move to such unusual setup. Q: Table1 has a primary key. Table2 joins to table1 using… or server does everything itself. Especially when using a CMS where DB structure is prepdefined A: MySQL Server will not automatically…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
… in each statement. You should try each statement for correctness before you attempt to convert it. You can easily check that… (convert.php) supports basic queries which use select/group by/join/where. You may not use sub-queries or any non-deterministic… in the data dictionary: mysql> select * from flexviews.mview_table where mview_id= flexviews.get_id(‘demo’,'dashboard_customer_sales’)\G…
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
… long running connections. Now let’s get started. Before We Start! But before we start, make sure you have enabled slow query… /*!50100 PARTITIONS*/ SELECT option_name, option_value FROM wp_options WHERE autoload = ‘yes’\G This is the actual part of the….term_id INNER JOIN wp_term_relationships AS tr ON tr.term_taxonomy_id = tt.term_taxonomy_id WHERE tt.taxonomy IN…
Post: Moving Subtrees in Closure Table Hierarchies
February 14, 2011 By 18 Comments
… the subtree starting at D, and place it under B. Before we move the subtree, we need to disconnect it from….descendant = d.descendant LEFT JOIN TreePaths AS x ON x.ancestor = d.ancestor AND x.descendant = a.ancestor WHERE d.ancestor = ‘D…, supertree.length+subtree.length+1 FROM TreePaths AS supertree JOIN TreePaths AS subtree WHERE subtree.ancestor = ‘D’ AND supertree.descendant = ‘B’; This…
Comment: Why MySQL could be slow with large tables ?
December 4, 2008 By 141 Comments
….unit_id)) FROM unit u RIGHT JOIN (SELECT up1.unit_id FROM unit_param up1 WHERE up1.unit_type_param_id = 24….unit_id = nmp0.unit_id RIGHT JOIN (SELECT up1.unit_id FROM unit_param up1 WHERE up1.unit_type_param_id = 23… query never responded, I had to cancel it (but not before it had run for 20min!! running on 100% CPU) However…
