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MySQL QA Episode 12: My server is crashing… Now what? For customers or users experiencing a crash

My server is crashing… Now what? This special episode in the MySQL QA Series is for customers or users experiencing a crash. A crash? Cheat sheet: https://goo.gl/rrmB9i Sever install & crash. Note this is as a demonstration: do …

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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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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 …

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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 …

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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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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 …

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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 …

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How to obtain the MySQL version from an FRM file

I recently helped a customer figure out why a minor version MySQL upgrade was indicating that some tables needed to be rebuilt. The mysql_upgrade program should be run for every upgrade, no matter how big …

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MySQL QA Episode 3: How to use the debugging tool GDB

Welcome to MySQL QA Episode 3: “Debugging: GDB, Backtraces, Frames and Library Dependencies” In this episode you’ll learn how to use debugging tool GDB. The following debugging topics are covered: 1. GDB Introduction 2. Backtrace, Stack …

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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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