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https://dev.mysql.com/doc/refman/8.4/en/alter-table.html
An exclusive metadata lock on the table may be taken briefly during preparation and execution phases of the operation. An exclusive metadata lock on the table may be taken briefly during the execution phase of the operation. The exception referred ... ALTER TABLE tbl_name [alter_option [, alter_option] ...] [partition_options] alter_option: { table_options | ADD [COLUMN] col_name column_definition [FIRST | AFTER col_name] | ADD [COLUMN] (col_name column_definition,...) | ADD {INDEX | KEY} [index_name] [index_type] (key_part,...) [index_option] ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-instrument-naming.html
Example names: wait/io/file/myisam/log wait/io/file/mysys/charset wait/lock/table/sql/handler wait/synch/cond/mysys/COND_alarm wait/synch/cond/sql/BINLOG::update_cond wait/synch/mutex/mysys/BITMAP_mutex wait/synch/mutex/sql/LOCK_delete ... An ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-table-handles-table.html
The Performance Schema exposes table lock information through the table_handles table to show the table locks currently in effect for each opened table handle. This information shows which table handles the server has open, how they are locked, and ...It is autosized by default; to configure the table size, set the performance_schema_max_table_handles system variable at server ...
https://dev.mysql.com/doc/refman/8.4/en/performance-schema-rwlock-instances-table.html
The rwlock_instances table lists all the rwlock (read write lock) instances seen by the Performance Schema while the server executes. An rwlock is a synchronization mechanism used in the code to enforce that threads at a given time can have access ...
https://dev.mysql.com/doc/mysql-shell/9.4/en/mysql-shell-utilities-dump-instance-schema.html
You can choose whether or not to lock the instance for backup during the dump for data consistency. If the consistent option is set to true, which is the default, the LOCK TABLES privilege on all dumped tables can substitute for the RELOAD privilege ... MySQL Shell's instance dump utility util.dumpInstance() and schema dump utility util.dumpSchemas(), support the export of all schemas or a selected schema from an on-premise MySQL instance into an Oracle Cloud Infrastructure Object Storage bucket or a set of local ...
https://dev.mysql.com/doc/refman/8.4/en/create-table-foreign-keys.html
Locking MySQL extends metadata locks, as necessary, to tables that are related by a foreign key constraint. Extending metadata locks prevents conflicting DML and DDL operations from executing concurrently on related tables. If a table is locked ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-enabling-monitors.html
For example: ===================================== 2014-10-16 18:37:29 0x7fc2a95c1700 INNODB MONITOR OUTPUT ===================================== The header for the standard InnoDB Monitor (INNODB MONITOR OUTPUT) is also used for the Lock Monitor ...
https://dev.mysql.com/doc/refman/8.4/en/server-status-variables.html
Handler_external_lock The server increments this variable for each call to its external_lock() function, which generally occurs at the beginning and end of access to a table instance. Innodb_buffer_pool_pages_misc The number of pages in the InnoDB ... The MySQL server maintains many status variables that provide information about its ...
https://dev.mysql.com/doc/refman/8.4/en/version-tokens-reference.html
Another set of functions permits version tokens to be locked and unlocked. mysql> SELECT version_tokens_lock_exclusive('lock1', 'lock2', 10); +-----------------------------------------------------+ | version_tokens_lock_exclusive('lock1', 'lock2', ... The following discussion serves as a reference to these Version Tokens elements: Version Tokens Functions Version Tokens System Variables Version Tokens Functions The Version Tokens plugin library includes several ...
https://dev.mysql.com/doc/relnotes/connector-cpp/en/news-8-0-12.html
(WL #11683) X DevAPI Notes Connector/C++ now supports NOWAIT and SKIP LOCKED lock contention modes to be used with lockExclusive() and lockShared() clauses of CRUD find/select operations (see Locking Read Concurrency with NOWAIT and SKIP LOCKED), ...