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Multiple purge threads in Percona Server 5.1.56 and MySQL 5.6.2

Part of the InnoDB duties, being an MVCC-implementing storage engine, is to get rid of–purge–the old versions of the records as they become obsolete.  In MySQL 5.1 this is done by the master InnoDB thread.  …

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How much could you benefit from MySQL 5.6 parallel replication?

I have heard this question quite often: “At busy times, our replicas start lagging quite frequently. We are using N schemas, so which performance boost could we expect from MySQL 5.6 parallel replication?” Here is …

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MySQL is crashing: a support engineer’s point of view

In MySQL QA Episode #12, “MySQL is Crashing, now what?,” Roel demonstrated how to collect crash-related information that will help Percona discover what the issue is that you are experiencing, and fix it. As a Support …

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The MySQL query cache: Worst enemy or best friend?

During the last couple of months I have been involved in an unusually high amount of performance audits for e-commerce applications running with Magento. And although the systems were quite different, they also had one …

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Why base64-output=DECODE-ROWS does not print row events in MySQL binary logs

Lately I saw many cases when users specified option --base64-output=DECODE-ROWS  to print out a statement representation of row events in MySQL binary logs just to get nothing. Reason for this is obvious: option --base64-output=DECODE-ROWS  does …

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MySQL QA Episode 9: Reducing Testcases for Experts: multi-threaded reducer.sh

Welcome to MySQL QA Episode 9. This episode will go more in-depth into reducer.sh: Reducing Testcases for Experts: multi-threaded reducer.sh We will explore how to use reducer.sh to do true multi-threaded testcase reduction – a world’s …

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MySQL QA Episode 8: Reducing Testcases for Engineers: tuning reducer.sh

Welcome to MySQL QA Episode 8: Reducing Testcases for Engineers: tuning reducer.sh Advanced configurable variables & their default/vanilla reducer.sh settings FORCE_SKIPV FORCE_SPORADIC TIMEOUT_COMMAND & TIMEOUT_CHECK MULTI_THREADS MULTI_THREADS_INCREASE QUERYTIMEOUT STAGE1_LINES SKIPSTAGE FORCE_KILL Some examples FORCE_SKIPV/FORCE_SPORADIC TIMEOUT_COMMAND/TIMEOUT_CHECK …

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Using Cgroups to Limit MySQL and MongoDB memory usage

Quite often, especially for benchmarks, I am trying to limit available memory for a database server (usually for MySQL, but recently for MongoDB also). This is usually needed to test database performance in scenarios with …

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MaxScale: A new tool to solve your MySQL scalability problems

Ever since MySQL replication has existed, people have dreamed of a good solution to automatically split read from write operations, sending the writes to the MySQL master and load balancing the reads over a set …

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Profiling MySQL queries from Performance Schema

When optimizing queries and investigating performance issues, MySQL comes with built in support for profiling queries aka SET profiling = 1; . This is already awesome and simple to use, but why the PERFORMANCE_SCHEMA alternative? Because profiling will be …

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