Information Schema INNODB_MUTEXES Table

The Information Schema INNODB_MUTEXES table displays statistics about InnoDB mutex and read-write lock waits, helping to identify internal contention.

The INNODB_MUTEXES table monitors mutex and rw locks waits. It has the following columns:

Column	Description
NAME	Name of the lock, as it appears in the source code.
CREATE_FILE	File name of the mutex implementation.
CREATE_LINE	Line number of the mutex implementation.
OS_WAITS	How many times the mutex occurred.

The CREATE_FILE and CREATE_LINE columns depend on the InnoDB/XtraDB version.

Current

The table provides information about all columns listed in the previous table.

< 10.2.2

The SHOW ENGINE INNODB STATUS statement provides similar information.

Examples

SELECT * FROM INNODB_MUTEXES;
+------------------------------+---------------------+-------------+----------+
| NAME                         | CREATE_FILE         | CREATE_LINE | OS_WAITS |
+------------------------------+---------------------+-------------+----------+
| &dict_sys->mutex             | dict0dict.cc        |         989 |        2 |
| &buf_pool->flush_state_mutex | buf0buf.cc          |        1388 |        1 |
| &log_sys->checkpoint_lock    | log0log.cc          |        1014 |        2 |
| &block->lock                 | combined buf0buf.cc |        1120 |        1 |
+------------------------------+---------------------+-------------+----------+

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