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How to know if a user never connected to the MySQL server since last boot ?

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


MySQL 8.0: Statements Latency Histograms

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


MySQL 8.0 : Digest Query Samples in Performance_Schema

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


MySQL 8.0 : meta-data added to Performance_Schema’s Instruments

In MySQL 8.0, the engineers have added useful meta-data to the table SETUP_INSTRUMENT. This table lists the classes of instrumented objects for which events can be collected. To the NAME, ENABLES and TIMED columns, were added PROPERTIES, VOLATILITY and DOCUMENTATION. Let’s have a quick look at these new columns: PROPERTIES can have the following values global_statistics: only global summaries are … Read More


TOP 10 MySQL 8.0 features for developers

MySQL 8.0 RC2 has just been released with a lot of new features compared to MySQL 5.7. In this blog post, I will list the top 10 new features that should excite developers. These functionalities are presented in descending order of preference of our MySQL Community. TOP 10 MySQL Document Store Default to utf8mb4 JSON enhancements CTEs Window Functions Descending … Read More


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