…greater frequency than 45 minutes, even as frequently as every minute, perhaps. The refresh method you select…table. If you …than COUNT(*). mysql> select count(*) cnt from order_lines\G *************************** 1. row *************************** cnt: 155187034 1 row in set (32.03 sec) mysql> select…
Post: Flexviews - part 3 - improving query performance using materialized views
April 4, 2011 By 20 Comments
Post: Identifying the load with the help of pt-query-digest and Percona Server
December 29, 2011 By 3 Comments
…remember to set it back to a value greater than 0, because otherwise you can have a really…in the overview section. So say if you were using the vanilla MySQL server, you would see ….000000 # InnoDB_pages_distinct: 973 SET timestamp=1325146286; select count(*) from auto_inc; Note that logging all …
Post: Multi Range Read (MRR) in MySQL 5.6 and MariaDB 5.5
March 21, 2012 By 10 Comments
… secondary index lookups, if the columns that… steps, without MRR: SELECT key_column, pk…MySQL 5.6, increase of 0.02s. But the query times for MariaDB 5.5 are greater than both MySQL 5.5 and MySQL…MySQL 5.6 code? As MRR was used in both MySQL 5.6 and MariaDB 5.5. Handler_mrr_rowid_refills counts…
Post: A case for MariaDB's Hash Joins
May 31, 2012 By Leave a Comment
… so if the left operand is big such that the size of the hash table built on it is greater than the join_buffer_size, then multiple hash tables would be created. For example if the left operand… with its EXPLAIN output as returned by MySQL 5.5 is as follows: SELECT o.*, count(*) as num_items FROM orders AS o…
Post: Tuning InnoDB Concurrency Tickets
May 24, 2010 By 5 Comments
…concurrency is greater than zero. On a stock install of MySQL, here are…mysql> SELECT COUNT(*) FROM test_table; — 3 Tickets Used +———-+ | COUNT(*) | +———-+ | 3 | +———-+ 1 row in set (0.00 sec) mysql…complete execution and exit InnoDB. If innodb_concurrency_tickets had been increased…
Post: How (not) to find unused indexes
October 16, 2009 By 2 Comments
…mysql> SELECT count(*) FROM Country; +———-+ | count(*) | +———-+ |     239 | +———-+ 1 row in set (0.00 sec) mysql> SELECT count(distinct(population)) FROM Country; +—————————–+ | count… have a population greater than 1000. An… which were not. If you are not …
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…MySQL will fail to start on a micro instance, simply decrease the values in the /etc/my.cnf file if…. Requires m1.small or greater. snap-073b6e68 shard-query… about 8x-10x better than a row store for…time). $ echo “select count(*) from ontime_fact;” | ./run_query Array ( [count(*)] => 135125787 ) 1…
