…mysql> show processlist; +——-+——+———–+———-+———+——+————————-+—————————–+———–+—————+———–+ | Id | User | Host | db | Command | Time | State…
Post: How to convert MySQL's SHOW PROFILES into a real profile
February 20, 2012 By 10 Comments
…to demonstrate: mysql> SET profiling=1; mysql> pager cat > /dev/null mysql> SELECT …@query_id GROUP BY STATE ORDER BY Total_R DESC; +———————-+———-+——-+——-+————–+ | STATE | Total_R | Pct_… | 0.000002 | 0.00 | 2 | 0.0000010000 | | end | 0.000002 | 0.00 | 1 | 0….
Post: Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit
November 24, 2011 By 2 Comments
…. Now, Valgrind does not need much introduction, especially to the MySQL server developers. The Valgrind Memcheck tool, which is synonymous with… counter values slightly smaller than they should be in the end. ==9090== Possible data race during write of size 8 at…_schema_table_state) (sql_show.cc:6238) ==9090== by 0x6A5E0C: JOIN::exec() (sql_select.cc:1863) ==9090== by 0x6A7D72: mysql_select(THD…
Post: Which Linux distribution for a MySQL database server? A specific point of view.
December 8, 2011 By 37 Comments
… MySQL packages upgraded from 5.1 to 5.5. The former were not fully uninstalled, the latter were in half-configured state. Obviously binutils has nothing to do with MySQL, but it would not install anyway…, but this can also be the case for any high-end/enterprise class equipment. Hardware vendors may release Linux drivers on…
Post: Reasons for MySQL Replication Lag
July 29, 2011 By 6 Comments
… change, though often subtle as computers are state machines and with no external and internal … pool size could cause performance problems. MySQL Restart MySQL Restarts may include recovery time but what … can hurt replication traffic well after they are ended. I’ve seen cases when overly eager …
Post: Shard-Query EC2 images available
May 11, 2011 By 2 Comments
…PRIMARY KEY (`airport_id`), KEY `CityName` (`CityName`), KEY `State` (`State`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 COMMENT=’… from 1988 to 2010′; mysql> use ontime1; Database changed mysql> show table status like ‘ontime_…[1] 12359 $ tail -f ./raw — Q1 … At the end, you will get a result output …
Post: Percona XtraDB Cluster 5.5.20 - Beta release
February 23, 2012 By 10 Comments
…deployments Support of Percona XtraBackup for Snapshot State Transfer. This feature is available in pre… Percona XtraDB Cluster works with databases created in MySQL / Percona Server Application compatibility. There is no… have a production-ready release by the end of March 2012. Links: We provide tar…
Post: Using any general purpose computer as a special purpose SIMD computer
May 16, 2011 By 6 Comments
…use the words of the Constitution of the United States of America as an example. It is my …serial version as run by the native database interface (MySQL): mysql> select word, md5(word), md5(reverse(word)), count(*) … add a small amount of serialization at the end. How does this work? Here is the most …
Post: MySQL caching methods and tips
April 4, 2011 By 4 Comments
… order to achieve the desired result. Your end users also care about response times because … for MySQL. Popular cache methods The MySQL query cache When the query cache is enabled, MySQL examines … mutex contention. Percona Server even has a state in the processlist ‘waiting on query cache mutex…
Post: MySQL Storage Engines - PBXT
May 14, 2007 By 6 Comments
…comparison for good and for bad. At its current state (as of the conference) PBXT does not offer …many applications if implemented well. It is too bad MySQL Users Conference only allowed 45 minutes for Storage …you can delay and group IOs together you may end up with a lot of extra writes. Besides …
