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https://dev.mysql.com/doc/refman/8.4/en/performance-schema-rwlock-instances-table.html
Shared-exclusive access is otherwise known as an sxlock and optimizes concurrency and improves scalability for read-write workloads. The rwlock_instances table lists all the rwlock (read write lock) instances seen by the Performance Schema while ...
https://dev.mysql.com/doc/refman/8.4/en/problems-with-float.html
Floating-point numbers sometimes cause confusion because they are approximate and not stored as exact values. A floating-point value as written in an SQL statement may not be the same as the value represented internally. Attempts to treat ...
https://dev.mysql.com/doc/refman/8.4/en/repair-table.html
[QUICK] [EXTENDED] [USE_FRM] REPAIR TABLE repairs a possibly corrupted table, for certain storage engines only. Although normally you should never have to run REPAIR TABLE, if disaster strikes, this statement is very likely to get back all your data ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features-flush.html
The FLUSH TABLES, ANALYZE TABLE, OPTIMIZE TABLE, and REPAIR TABLE statements are written to the binary log and thus replicated to replicas. Some forms of the FLUSH statement are not logged because they could cause problems if replicated to a ...
https://dev.mysql.com/doc/refman/8.4/en/replication-options-binary-log.html
Typically, the benefits of setting a delay outweigh the drawbacks, but tuning should always be carried out to determine the optimal setting. Startup Options Used with Binary Logging System Variables Used with Binary Logging You can use the mysqld ...
https://dev.mysql.com/doc/refman/8.4/en/replication-solutions-backups-read-only.html
Note The instructions in this section place the server to be backed up in a state that is safe for backup methods that get the data from the server, such as mysqldump (see Section 6.5.4, “mysqldump — A Database Backup Program”). You should not ...
https://dev.mysql.com/doc/refman/8.4/en/select-benchmarking.html
The built-in MySQL functions are typically highly optimized, but there may be some exceptions. To measure the speed of a specific MySQL expression or function, invoke the BENCHMARK() function using the mysql client program. The return value is ...
https://dev.mysql.com/doc/refman/8.4/en/server-option-variable-reference.html
The following table lists all command-line options, system variables, and status variables applicable within mysqld. The table lists command-line options (Cmd-line), options valid in configuration files (Option file), server system variables ...
https://dev.mysql.com/doc/refman/8.4/en/server-shutdown.html
For additional information about thread termination, see Section 15.7.8.4, “KILL Statement”, in particular for the instructions about killed REPAIR TABLE or OPTIMIZE TABLE operations on MyISAM tables. The server shutdown process takes place as ...
https://dev.mysql.com/doc/refman/8.4/en/set-operations.html
If ORDER BY appears without LIMIT within a query block, it is optimized away because it has no effect in any case. Result Set Column Names and Data Types Set Operations with TABLE and VALUES Statements Set Operations using DISTINCT and ALL Set ...