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https://dev.mysql.com/doc/refman/8.4/en/performance-schema-variables-info-table.html
The variables_info table shows, for each system variable, the source from which it was most recently set, and its range of values. VARIABLE_SOURCE The source from which the variable was most recently set: COMMAND_LINE The variable was set on the ...
https://dev.mysql.com/doc/refman/8.4/en/persisted-system-variables.html
The MySQL server maintains system variables that configure its operation. A system variable can have a global value that affects server operation as a whole, a session value that affects the current session, or both. Many system variables are ...
https://dev.mysql.com/doc/refman/8.4/en/prepare.html
PREPARE stmt_name FROM preparable_stmt The PREPARE statement prepares a SQL statement and assigns it a name, stmt_name, by which to refer to the statement later. The prepared statement is executed with EXECUTE and released with DEALLOCATE PREPARE.
https://dev.mysql.com/doc/refman/8.4/en/preventing-use-of-optimizer-trace.html
If, for some reason, you wish to prevent users from seeing traces of their queries, start the server with the options shown here: --maximum-optimizer-trace-max-mem-size=0 --optimizer-trace-max-mem-size=0 This sets the maximum size to 0 and prevents ...
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/processlist-access.html
The following discussion enumerates the sources of process information, the privileges required to see process information, and describes the content of process list entries. The other sources have negative performance consequences because they ...
https://dev.mysql.com/doc/refman/8.4/en/rename-table.html
RENAME TABLE tbl_name TO new_tbl_name [, tbl_name2 TO new_tbl_name2] ... You must have ALTER and DROP privileges for the original table, and CREATE and INSERT privileges for the new table. You can rename tables locked with a LOCK TABLES statement, ...
https://dev.mysql.com/doc/refman/8.4/en/replica-io-thread-states.html
The following list shows the most common states you see in the State column for a replication I/O (receiver) thread on a replica server. This state also appears in the Replica_IO_State column displayed by SHOW REPLICA STATUS, so you can get a good ...
https://dev.mysql.com/doc/refman/8.4/en/replica-sql-thread-states.html
The following list shows the most common states you may see in the State column for a replication SQL thread on a replica server. Monitoring tools that work with these instrumentation names might be impacted. If the incompatible changes have an ...
https://dev.mysql.com/doc/refman/8.4/en/replication-features-memory.html
When a replication source server shuts down and restarts, its MEMORY tables become empty. To replicate this effect to replicas, the first time that the source uses a given MEMORY table after startup, it logs an event that notifies replicas that the ...