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30.4.3.42 The user_summary_by_file_io and x$user_summary_by_file_io Views

https://dev.mysql.com/doc/refman/8.0/en/sys-user-summary-by-file-io.html

Rows for which the USER column in the underlying Performance Schema table is NULL are assumed to be for background threads and are reported with a host name of background. By default, rows are sorted by descending total file I/O latency. The ...

30.4.3.44 The user_summary_by_stages and x$user_summary_by_stages Views

https://dev.mysql.com/doc/refman/8.0/en/sys-user-summary-by-stages.html

7.6.3.4 Thread Pool Tuning

https://dev.mysql.com/doc/refman/8.0/en/thread-pool-tuning.html

The default value of 6 (60ms) is suitable for servers that primarily execute very simple statements. Assuming that the tp_thread_group_stats table is enabled, you can use the following query to determine the fraction of executed statements that ...

13.2.3 The TIME Type

https://dev.mysql.com/doc/refman/8.0/en/time.html

Note that because '00:00:00' is itself a valid TIME value, there is no way to tell, from a value of '00:00:00' stored in a table, whether the original value was specified as '00:00:00' or whether it was invalid. MySQL retrieves and displays TIME ...

10.15.3 Traceable Statements

https://dev.mysql.com/doc/refman/8.0/en/traceable-statements.html

Statements which are traceable are listed here: SELECT INSERT REPLACE UPDATE DELETE EXPLAIN with any of the preceding statements SET DO DECLARE, CASE, IF, and RETURN as used in stored routines CALL Tracing is supported for both INSERT and REPLACE ...

6.2.7 Connection Transport Protocols

https://dev.mysql.com/doc/refman/8.0/en/transport-protocols.html

The following table shows the permissible values for --protocol and indicates the applicable platforms for each value. For programs that use the MySQL client library (for example, mysql and mysqldump), MySQL supports connections to the server based ...

10.15.4 Tuning Trace Purging

https://dev.mysql.com/doc/refman/8.0/en/tuning-trace-purging.html

A subsequent SELECT from the OPTIMIZER_TRACE table returns the first limit traces of the offset oldest stored traces (if offset >= 0), or the first limit traces of the -offset newest stored traces (if offset < 0). Thus, if a statement contains ...

Chapter 5 Tutorial

https://dev.mysql.com/doc/refman/8.0/en/tutorial.html

If you are interested only in accessing an existing database, you may want to skip the sections that describe how to create the database and the tables it contains. This chapter provides a tutorial introduction to MySQL by showing how to use the ...

3.8 Upgrading MySQL with the MySQL Yum Repository

https://dev.mysql.com/doc/refman/8.0/en/updating-yum-repo.html

Upgrading MySQL Upgrade MySQL and its components by the following command, for platforms that are not dnf-enabled: sudo yum update mysql-server For platforms that are dnf-enabled: sudo dnf upgrade mysql-server Alternatively, you can update MySQL by ... For supported Yum-based platforms (see Section 2.5.1, “Installing MySQL on Linux Using the MySQL Yum Repository”, for a list), you can perform an in-place upgrade for MySQL (that is, replacing the old version and then running the new version using the old data files) with the MySQL Yum ...

10.3.7 Verifying Index Usage

https://dev.mysql.com/doc/refman/8.0/en/verifying-index-usage.html

Always check whether all your queries really use the indexes that you have created in the tables. Use the EXPLAIN statement, as described in Section 10.8.1, “Optimizing Queries with EXPLAIN”.

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