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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.  …


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 …


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 …


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 …


Bypassing SST in Percona XtraDB Cluster with binary logs

In my previous post, I used incremental backups in Percona XtraBackup as a method for rebuilding a Percona XtraDB Cluster (PXC) node without triggering an actual SST. Practically this reproduces the SST steps, but it …


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 …


Update on the InnoDB double-write buffer and EXT4 transactions

In a post, written a few months ago, I found that using EXT4 transactions with the “data=journal” mount option, improves the write performance significantly, by 55%, without putting data at risk. Many people commented on …


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 …


Optimizing Percona XtraDB Cluster for write hotspots

Some applications have a heavy write workload on a few records – for instance when incrementing a global counter: this is called a write hotspot. Because you cannot update the same row simultaneously from multiple …


Percona Server 5.6.24-72.2 is now available

Percona is glad to announce the release of Percona Server 5.6.24-72.2 on May 8, 2015. Download the latest version from the Percona web site or from the Percona Software Repositories. Based on MySQL 5.6.24, including all the bug …