…functions supported, except GROUP_CONCAT and AVG(distinct). **non-deterministic functions…COUNT(*). mysql> select count(*) cnt from order_lines\G *************************** 1. row *************************** cnt: 155187034 1 row in set (32.03 sec) mysql> select sum(total…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
Post: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 5 Comments
…function, and treat any size cluster of Turing computers as a specialized purpose SIMD computer with respect to your function…MySQL): mysql> select word, md5(word), md5(reverse(word)), count(*) from words2 group…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
…in the equijoin condition. The hash table is accessed by using a hash function…total dataset size is 4.8G. Let me show the breakdown of dataset size by the tables that I have used in…in_group…with its EXPLAIN output as returned by MySQL 5.5 is as follows: SELECT o.*, count…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
…MySQL…in_groupblogpercona.commanual innodb_log_group…in_memoryblogpercona.commanual logblogpercona.commanual log_binblogpercona.commanual log_binblogpercona.commanual log_bin_indexblogpercona.commanual log_bin_trust_function…in_cacheblogpercona.commanual Qcache_total…with…
Post: MySQL Indexing Best Practices: Webinar Questions Followup
August 16, 2012 By 4 Comments
…total size or less to almost 100%. When your go from working set what fits in…, COUNT(user_id) AS user_count FROM user_competition_entry GROUP… on a table with 11M rows I’ve seen …in index order MySQL gets data in already sorted order and looks at “one group at the time”, computing aggregate functions…
