Many of you already know how to retrieve the size of your dataset, schemas and tables in MySQL. To summarize, below are the different queries you can run: Dataset Size I the past I was using something like this : But now with sys schema being installed by default, I encourage you to use some of the formatting functions provided … Read More
If you are a MySQL DBA for a long time (like me), it’s very complicated to get rid of bad habits. One of them I really need to change is the way to retrieve the list of all the running queries (processlist). Usually, I use SHOW FULL PROCESSLIST which is very convenient, but like querying the Information_Schema, this statement has … Read More
Performance_Schema is used most of the time to get metrics about queries and connections. But it can also provide other very useful information. So today, I will show you how you can see a list of users that didn’t connect to MySQL since we restarted it (since last reboot). SELECT DISTINCT mu.user FROM mysql.user mu LEFT JOIN performance_schema.users psu ON … Read More
At the end we all agree that what really matters is the Query Response Time, isn’t it ? MySQL 8.0 engineers have added more visibility in the summary tables as explained in this previous post. But to add more details, now the Performance_Schema also collects the statements latency and provide their distribution thanks to the collected histogram data. Two tables … Read More
Today, yet another blog post about improvements in MySQL 8.0 related to Performance_Schema. Before MySQL 8.0 it was not always easy to get an example of the queries you could find in Performance_Schema when looking for statements summaries. You had to link several tables (even from sys) to achieve this goal as I explained it in this post. Now in … Read More
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