… in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a… optimizer enhancement Index Condition Pushdown (ICP). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
Post: MySQL Session variables and Hints
December 28, 2006 By 2 Comments
MySQL has two ways to find tune execution of particular query. First is MySQL Hints, such as SQL_BIG_RESULT, STRAIGHT_JOIN, FORCE…_size=DEFAULT after executing the query. I noticed in production hints are used much more frequently than setting session variables for… it is not created dynamically some complex way) – adding extra MySQL calls with possibly their own error control is more complicated…
Post: Troubleshooting MySQL Upgrade Performance Regressions
February 15, 2012 By Leave a Comment
… it without side load. Setting up 2 MySQL Servers side by side (for example with MySQL Sandbox) can especially be helpful. Once you have spotted the query which performs differently between MySQL Server versions you should: Check Query Plan Run EXPLAIN to… application by changing how query is written and provide the hints. Check Query Execution If query execution plan looks the same…
Post: Guidance for MySQL Optimizer Developers
September 20, 2009 By 4 Comments
… spend large portion of my life working on MySQL Performance Optimization and so MySQL Optimizer is quite important to me. For probably… to stick to old optimizer behavior with new MySQL Version. Make Cost Model Adjustable MySQL Optimizer looks at query plan in terms… well as simply hints. Any way MySQL could possibly execute query should be possible to force with hints. In MySQL 4.0 this was…
Post: SELECT LOCK IN SHARE MODE and FOR UPDATE
August 6, 2006 By 51 Comments
… comparing locking hints in MySQL and SQL Server. In MySQL/Innodb LOCK IN SHARE MODE and SELECT FOR UPDATE are more than hints. Behavior will be different from normal SELECT statements. Here is simple example: SESSION1: mysql> begin; Query OK… of shared locks on Innodb table but no updates. Supporting MySQL hints “HIGH_PRIORITY” and “LOW_PRIORITY” would probably be good start…
Post: Debugging sleeping connections with MySQL
February 8, 2007 By 28 Comments
… timeouts properly. Or may be you have several connections to MySQL server and right now running query which takes that long… which that process is processing and so get few more hints on what may be happening or even get repeatable example… process are not only helpful to debug sleeping connections with MySQL but many other cases when you see web application locking…
Post: Percona Server 5.1.57 with Galera 0.8.1
July 28, 2011 By Leave a Comment
Codership team announced availability of MySQL/Galera 0.8.1, which is minor release, but actually … a lot). As part of my evaluation activity I ported MySQL/Galera 0.8.1 to Percona Server/Galera 0.8… fact that not everybody has fun from compiling source code (hint, hint for Drizzle developers), that is why I also made binaries…
Post: Announcing Percona Toolkit Release 2.0.3
February 6, 2012 By 2 Comments
… on the disk or waiting on the queue scheduler (cfq, hint hint). Finally, it has transparency, so you can read the documentation…
Post: 10+ Ways to Crash or Overload MySQL
November 13, 2007 By 20 Comments
… been normally treated very quickly by MySQL. The moment you give someone access to MySQL Server, all MySQL Security guarantees is you can… limit and MySQL will crash when one of internal memory allocations would unexpectedly fail. To give you couple of hints: Temporary Tables… can reduce system performance beyond being functional. General Overload As MySQL does not have much of resource utilization control you can…
Post: MySQL Support or Support for MySQL ? MySQL Trademark Policies
October 26, 2007 By 11 Comments
… named “MySQL Support” or “MySQL Consulting” The most well case known with MySQL Trademark enforcement so far is perhaps MySQL Front which MySQL asked to be renamed but MySQL… Projects are smarter with naming, like InnoTop or MyTop which hint on the product names but do not use them directly…
