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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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MySQL replication primer with pt-table-checksum and pt-table-sync

MySQL replication is a process that allows you to easily maintain multiple copies of MySQL data by having them copied automatically from a master to a slave database. It’s essential to make sure the slave …

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New PERFORMANCE_SCHEMA defaults in MySQL 5.7.7

I thought it was worth a moment to reiterate on the new Performance Schema related defaults that MySQL 5.7.7 brings to the table, for various reasons. For one, most of you might have noticed that …

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The future of MySQL quality assurance: Introducing pquery

Being a QA Engineer, how would you feel if you had access to a framework which can generate 80+ crashes – a mix of hitting developer introduced assertions (situations that should not happen), and serious unforeseen binary …

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The MySQL Query Cache: How it works, plus workload impacts (good and bad)

Query caching is one of the prominent features in MySQL and a vital part of query optimization. It is important to know how it works as it has the potential to cause significant performance improvements – …

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File carving methods for the MySQL DBA

This is a long overdue blog post from London’s 44con Cyber Security conference back in September. A lot of old memories were brought to the front as it were; the one I’m going to cover in …

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Log rotate and the (deleted) MySQL log file mystery

Did your logging stop working after you set up logrotate? Then this post might be for you. Some time ago, Peter Boros wrote about Rotating MySQL Slow Logs safely, explaining the steps of a “best …

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How to deal with MySQL deadlocks

A deadlock in MySQL happens when two or more transactions mutually hold and request for locks, creating a cycle of dependencies. In a transaction system, deadlocks are a fact of life and not completely avoidable. …

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MySQL 101: Monitor Disk I/O with pt-diskstats

Here on the Percona Support team we often ask customers to retrieve disk stats to monitor disk IO and to measure block devices iops and latency. There are a number of tools available to monitor …

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Reducer.sh – A powerful MySQL test-case simplification/reducer tool

Let me start by saying a big “thank you” to the staff at Oracle for deciding to open source reducer.sh. It’s a tool I developed whilst I was working for them several years ago. Its …

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