…MySQL 5.6, when the workload fits entirely in memory, because there is no extra cost for memory access at random locations versus memory…MySQL 5.6 are reporting high numbers for Innodb_rows_read, which is completely in…
Post: Index Condition Pushdown in MySQL 5.6 and MariaDB 5.5 and its performance impact
March 12, 2012 By 12 Comments
I have been working with Peter in preparation for the talk comparing the optimizer enhancements in MySQL 5.6 and MariaDB 5.5. We are taking a look at and benchmarking optimizer enhancements one by one. So in… new optimizer enhancement Index Condition Pushdown (ICP). Its available in both MySQL 5.6 and MariaDB 5.5 Now let’s take…
Post: Side load may massively impact your MySQL Performance
November 13, 2011 By 7 Comments
… is staying about the same when we run tests concurrently because Sysbench should run completely in memory and use a lot of CPU …=17600000 –mysql-user=msandbox –mysql-password=msandbox –mysql-socket=/tmp/mysql_sandbox5516.sock prepare Running Sysbench and MySQLDump. Note we run them in the loop …
Post: MySQL-Memcached or NOSQL Tokyo Tyrant - part 2
October 16, 2009 By 8 Comments
… focus on running the same tests against Tokyo Tyrant. Wow that’s shockingly fast isn’t it! I guess being completely in memory helps for this app. What is very interesting is accessing 100% of the data in memcached gives very… benchmarks for mixing MySQL and Memcached in my tests: In this case I think Fast was slower when working with MySQL with a 256m…
Post: Helgrinding MySQL with InnoDB for Synchronisation Errors, Fun and Profit
November 24, 2011 By 2 Comments
…the MySQL server development: there is support for it in the MySQL Test …running one. ==9090== Possible data race during read of size 8 at 0xff27758 by thread #4 ==9090== at 0x6B67C51: log_io_complete…memory barrier, that is when we read the waiters field next, the read must be serialized in memory…
Post: Ultimate MySQL variable and status reference list
January 8, 2011 By 4 Comments
… MySQL manual, especially the option …Com_xa_startblogpercona.commanual completion_typeblogpercona.commanual Compressionblogpercona….wait_timeoutblogpercona.commanual locked_in_memoryblogpercona.commanual logblogpercona….shared_memoryblogpercona.commanual shared_memory_base_nameblogpercona.commanual …
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…mysql –user=mysql –pid-file=/var/run/mysqld/mysqld.pid –skip-external-locking –port=3306 –socket=/var/db/mysql/mysql… time to complete an action longer. If your application runs very short queries…in-memory temporary table will be converted to an on-disk table, which is an expensive operation. In…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 139 Comments
…indexes. In fact even MySQL optimizer currently does not take it into account. For In memory workload … completely disk bound can be very slow. One of the reasons elevating this problem in MySQL …data sets. In MySQL single query runs as single thread (with exeption of MySQL Cluster) and MySQL issues …
Post: The MySQL optimizer, the OS cache, and sequential versus random I/O
April 28, 2008 By 17 Comments
…will run for days and never complete. No one ever let it finish to see how long it would run. How…the fact table, and do index lookups in the two dimension tables. MySQL doesn’t want to choose this …are small and they stay in memory, in the OS cache. (They don’t get evicted from memory by the cache’s…
Post: MySQL Server Memory Usage
May 17, 2006 By 18 Comments
… to run. Unfortunately this is as much close to impossible to be impractical. Here is why: List of rarely considered MySQL Server Memory… able to run MySQL server out of memory MyISAM buffers. MyISAM may allocate buffer which is large enough to contain largest record in the… storage engines being released for MySQL by various parties. I do not pretend this to be complete list. On the contrary I…
