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Advanced Query Tuning in MySQL 5.6 and MySQL 5.7 Webinar: Q&A

Thank you for attending my July 22 webinar titled “Advanced Query Tuning in MySQL 5.6 and 5.7” (my slides and a replay available here). As promised here is the list of questions and my answers …

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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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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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MySQL indexing 101: a challenging single-table query

We discussed in an earlier post how to design indexes for many types of queries using a single table. Here is a real-world example of the challenges you will face when trying to optimize queries: …

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Generated (Virtual) Columns in MySQL 5.7 (labs)

About 2 weeks ago Oracle published the MySQL 5.7.7-labs-json version which includes a very interesting feature called “Generated columns” (also know as Virtual or Computed columns). MariaDB has a similar feature as well: Virtual (Computed) Columns. The …

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Identifying useful info from MySQL row-based binary logs

As a MySQL DBA/consultant, it is part of my job to decode the MySQL binary logs – and there are a number of reasons for doing that. In this post, I’ll explain how you can …

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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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MySQL’s INNODB_METRICS table: How much is the overhead?

Starting with MySQL 5.6 there is an INNODB_METRICS table available in INFORMATION_SCHEMA which contains some additional information than provided in the SHOW GLOBAL STATUS output – yet might be more lightweight than PERFORMANCE_SCHEMA. Too bad …

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Data inconsistencies on MySQL replicas: Beyond pt-table-checksum

Percona Toolkit’s pt-table-checksum is a great tool to find data inconsistencies between a MySQL master and its replicas. However it is sometimes not enough to know that there are inconsistencies and let pt-table-sync fix the …

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