… secondary keys from deferred key creation optimization. Bug fixed #1081016 (Alexey Kopytov). Percona Server for MySQL was built with YaSSL which could… query which opened that table. Bug fixed #1127008 (Sergei Glushchenko). Fix for bug #1070856 introduced a regression in Percona Server for MySQL…
Post: Virident vCache vs. FlashCache: Part 2
May 17, 2013 By 3 Comments
… more sense to configure MySQL as if it were using SSD storage or to just use an optimized HDD storage configuration? After creating a vCache device with the default configuration, I started with a baseline HDD configuration for MySQL… join_buffer_size = 4M thread_cache_size = 1000 query_cache_size = 0 query_cache_type = 0 ft_min_word_len = 4 thread…
Post: MySQL 5.6.10 Optimizer Limitations: Index Condition Pushdown
March 14, 2013 By 2 Comments
… the webinar: “Learn How MySQL 5.6 Makes Query Optimization Easier” for more tips on the 5.6 optimizer[/caption] While preparing the webinar… optimization strategies. Even row-level operation counters are sometimes not enough. Do you want to know more about the MySQL 5.6 query optimization…
Post: How to find MySQL queries worth optimizing ?
September 11, 2012 By 6 Comments
… find out queries which should be optimized. By looking at pt-query-digest report it is easy to find slow queries or queries which cause… which are found and returned up to the top level MySQL part for processing are counted the Rows_examined remains zero… is the easy way to see if query is worth optimizing ? – see how many rows query sends after group by, distinct and aggregate…
Post: The MySQL optimizer, the OS cache, and sequential versus random I/O
April 28, 2008 By 17 Comments
… the optimizer not choose the faster one? That’s what this post is about. Let’s start with the MySQL query optimizer. The optimizer tries… cost for a query, then choose the query plan that has the lowest cost. The unit of cost for the MySQL query optimizer is a… is sometimes needed to provide the missing information. If the MySQL optimizer were right and each of these had to go to…
Post: MySQL: Followup on UNION for query optimization, Query profiling
August 14, 2006 By 14 Comments
… you do not have to use the union. So changing query to: mysql> SELECT sql_no_cache name FROM people WHERE age… there are really different types of ranges in MySQL. IN range allows to optimize lookups on the second key part, while BETWEEN… queries to see what exactly happens during query execution – very helpful for MySQL Performance optimization: mysql> flush status; Query OK, 0 rows affected (0.00 sec) mysql…
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
… helpful for MySQL Performance optimization tasks but there are number of things you need to know. First let me clarify what MySQL Query Cache… being confused, thinking MySQL Query Cache is the same as Oracle Query Cache – meaning cache where execution plans are cached. MySQL Query Cache is not…
Post: Is MySQL 5.6 slower than MySQL 5.5?
February 18, 2013 By 23 Comments
… hitting MySQL Support Team at Oracle. For a number of simple workloads I would expect to see some slowdown – MySQL 5.6 Optimizer got a lot smarter and the more plans have to be considered for the query the more time the query optimization… advantage of any of new MySQL 5.6 optimizations so it is geared towards worse case scenario for MySQL 5.6 performance. Here…
Post: Percona Live MySQL Conference and Expo 2013 – News from the Committee – Tutorial Selection Complete
December 3, 2012 By 1 Comment
… afternoon follow up to Rick’s talk might be: Advanced query optimizer tuning and analysis This 3 hour session is being given… from the Monty Program and focuses in on how the query optimizer does what it does, why it does it, and how… when this was not the case at a MySQL conference. There are several MySQL HA related tutorials: Using Tungsten Replicator to solve…
Post: MySQL Query Cache WhiteSpace and comments
March 20, 2008 By 9 Comments
… post on MySQL Query Cache Gerry pokes me as I’m all wrong and both comments and whitespace are fixed in MySQL 5… which just does the same query. I did this as command line client is known to optimize queries sometimes by skipping “unnecessary” comments. So here is the command line run: mysql> select /* my little comment…
