SHOW ENGINE engine_name {STATUS | MUTEX}
SHOW ENGINE
displays operational information about a storage engine. The following statements currently are supported:
SHOW ENGINE INNODB STATUS SHOW ENGINE INNODB MUTEX SHOW ENGINE PERFORMANCE_SCHEMA STATUS
If the Sphinx Storage Engine is installed, the following is also supported:
SHOW ENGINE SPHINX STATUS
See SHOW ENGINE SPHINX STATUS
.
Older (and now removed) synonyms were SHOW INNODB STATUS
for SHOW ENGINE INNODB STATUS
and SHOW MUTEX STATUS
for SHOW ENGINE INNODB MUTEX
.
SHOW ENGINE BDB LOGS
formerly displayed status information about BDB log files. It was deprecated in MySQL 5.1.12 and removed in MariaDB and MySQL 5.5, so now produces an error.
SHOW ENGINE INNODB STATUS
displays extensive information from the standard InnoDB Monitor about the state of the InnoDB storage engine. See SHOW ENGINE INNODB STATUS
for more.
SHOW ENGINE INNODB MUTEX
displays InnoDB mutex statistics.
The statement displays the following output fields:
UNIV_DEBUG
was defined at compilation time (for example, in include/univ.h in the InnoDB part of the source tree). Only the os_waits
value is displayed if UNIV_DEBUG
was not defined. Without UNIV_DEBUG
, the information on which the output is based is insufficient to distinguish regular mutexes and mutexes that protect rw-locks (which allow multiple readers or a single writer). Consequently, the output may appear to contain multiple rows for the same mutex. Information from this statement can be used to diagnose system problems. For example, large values of spin_waits and spin_rounds may indicate scalability problems.
The information_schema.INNODB_MUTEXES
table provides similar information.
This statement shows how much memory is used for performance_schema
tables and internal buffers.
The output contains the following fields:
performance_schema
. performance_schema
word, followed by a dot and an attribute. Internal buffers names are enclosed by parenthesis. performance_schema
means that the attribute refers to the whole database (it is a total). The following attributes are shown, in this order, for all tables:
performance_schema
, this is the result of row_size
* row_count
. For internal buffers, the attributes are:
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Licensed under the Creative Commons Attribution 3.0 Unported License and the GNU Free Documentation License.
https://mariadb.com/kb/en/show-engine/