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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 …


PXC – Incremental State transfers in detail

IST Basics State transfers in Galera remain a mystery to most people.  Incremental State transfers (as opposed to full State Snapshot transfers) are used under the following conditions: The Joiner node reports Galera a valid …


MySQL QA Episode 11: Valgrind Testing: Pro’s, Con’s, Why and How

Today’s episode is all about Valgrind – from the pro’s to the con’s, from the why to the how! This episode will be of interest to anyone who is or wants to work with Valgrind on …


MySQL QA Episode 10: Reproducing and Simplifying: How to get it Right

Welcome to the 10th episode in the MySQL QA series! Today we’ll talk about reproducing and simplifying: How to get it Right. Note that unless you are a QA engineer stuck on a remote, and …


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 …


Multi-source replication in MySQL 5.7 vs Tungsten Replicator

MySQL 5.7 comes with a new set of features and multi-source replication is one of them. In few words this means that one slave can replicate from different masters simultaneously. During the last couple of …


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 …


InnoDB vs TokuDB in LinkBench benchmark

Previously I tested Tokutek’s Fractal Trees (TokuMX & TokuMXse) as MongoDB storage engines – today let’s look into the MySQL area. I am going to use modified LinkBench in a heavy IO-load. I compared InnoDB …


The Q&A: Creating best-in-class backup solutions for your MySQL environment

Thank you for attending my July 15 webinar, “Creating Best in Class Backup solutions for your MySQL environment.” Due to the amount of content we discussed and some minor technical difficulties faced near the end …


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 …