June 19, 2013

Post: 10+ Ways to Crash or Overload MySQL

November 13, 2007 By 20 Comments

…. General Overload As MySQL does not have much of resource utilization control you can simply run heavy queries to get MySQL Server barely functional. The limits which exist are not really helpful as they do not define query complexity… old MySQL versions which typically have more issues. P.P.S Nothing I write here is security hole which is unknown to MySQL…

Filed Under: Insight for DBAs Tagged With:

Post: New MySQL Community Release Policies published

August 9, 2007 By 9 Comments

…of slow queries over half a year ago. These patches had a good support from MySQL Professional …on its own to build true community MySQL version for production ready version. There are great patches out … is different in each case. People get upset with MySQL because it starts to give back less…

Filed Under: Events and Announcements Tagged With:

Post: DROP TABLE and stalls: Lazy Drop Table in Percona Server and the new fixes in MySQL

June 22, 2012 By 33 Comments

… a great extent but does not get rid of it completely. In the new releases of MySQL (versions >= 5.5.23) work has…/write queries against a 20M rows table: sysbench –test=oltp –oltp-table-size=20000000 –mysql-table-engine=innodb –mysql-socket=/tmp/mysql_sandbox5524.sock –mysql… in QPS whenever table is dropped, MySQL 5.5.23 does show an improvement over MySQL version prior to 5.5.23, as…

Filed Under: Benchmarks, Insight for DBAs, MySQL

Post: Profiling MySQL Memory Usage With Valgrind Massif

January 9, 2013 By 3 Comments

…sharp memory increase after executing a particular query. Or, maybe mysqld is seemingly using …get the Valgrind program. Though you could use the latest version which comes with your OS (think yum or apt-get…event::read_log_event(st_io_cache*, st_mysql_mutex*, Format_description_log_event const*) (in…

Filed Under: Insight for DBAs, Insight for Developers, MySQL, Quality Assurance

Post: Flexviews - part 3 - improving query performance using materialized views

April 4, 2011 By 20 Comments

…); Query OK, 0 rows affected (42 min 42.14 sec) But the incrementally refreshable version does not take long to refresh: mysql> call flexviews.refresh( -> flexviews.get_id(‘demo’, -> ‘dashboard_customer_sales’),’BOTH’,NULL); Query OK…

Filed Under: Insight for DBAs, MySQL

Post: How Percona does a MySQL Performance Audit

November 24, 2008 By 17 Comments

… port, etc etc. Nothing unusual. Next I check what the MySQL version is, and I check (with the ‘file’ command) whether /usr… query.) If it’s not possible to use a patched binary, we can use MySQL Proxy, packet sniffing, or other techniques to get… then tell me how much total gain I can get from it. Queries are not just “bad” or “good” — it’s a…

Filed Under: Insight for Developers Tagged With:

Post: MySQL Query Cache

July 27, 2006 By 70 Comments

… their result set but MySQL has no way to identify which one of them would so it gets rid of all of… than individual queries. No control on invalidation Table granularity is often too bad. With other caches you may implement version based or timeout based invalidation which can offer much better hit ratio for certain application. It is not that fast Query…

Filed Under: Insight for DBAs Tagged With:

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

March 4, 2013 By 7 Comments

…, if we change the above query to be “+james +peterson arizona” then we might expect to get back multiple matches containing the… we were looking for queries containing the word “MySQL” – odds are that an article which has 10 instances of “MySQL” might be more… how your application behaves as a result of a major MySQL version upgrade before rolling it into production! Percona has tools (pt…

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

Post: MySQL 5.5 and MySQL 5.6 default variable values differences

February 21, 2013 By 8 Comments

… the values from MySQL 5.5.30 and MySQL 5.6.10 to the different tables and ran the query: mysql [localhost] {msandbox} (test… | | INNODB_VERSION | 5.5.30 | 1.2.10 | | INNODB_BUFFER_POOL_INSTANCES | 1 | 8 | | QUERY_CACHE_SIZE | 0 | 1048576 | | SLOW_QUERY_LOG_FILE… but getting MyISAM because Innodb was disabled for some reason was very error prone gotcha. Note this is as far as MySQL…

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

Post: Guidance for MySQL Optimizer Developers

September 20, 2009 By 4 Comments

… stick to old optimizer behavior with new MySQL Version. Make Cost Model Adjustable MySQL Optimizer looks at query plan in terms of disk IOs… way MySQL could possibly execute query should be possible to force with hints. In MySQL 4.0 this was the case, in recent versions… by changing the code) is the data Optimizer Team can get back from customers and community – it because very easy for…

Filed Under: Insight for Developers, MySQL Tagged With:
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