Syntax:
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 {NDB | NDBCLUSTER} STATUS
SHOW ENGINE PERFORMANCE_SCHEMA STATUS

SHOW ENGINE INNODB STATUS displays extensive information from the
standard InnoDB Monitor about the state of the InnoDB storage engine.
For information about the standard monitor and other InnoDB Monitors
that provide information about InnoDB processing, see
http://dev.mysql.com/doc/refman/5.5/en/innodb-monitors.html.

SHOW ENGINE INNODB MUTEX displays InnoDB mutex statistics. The
statement displays the following fields:

o Type

  Always InnoDB.

o Name

  The source file where the mutex is implemented, and the line number
  in the file where the mutex is created. The line number may change
  depending on your version of MySQL.

o Status

  The mutex status. This field displays several values if UNIV_DEBUG
  was defined at MySQL compilation time (for example, in include/univ.i
  in the InnoDB part of the MySQL source tree). If UNIV_DEBUG was not
  defined, the statement displays only the os_waits value. In the
  latter case (without UNIV_DEBUG), the information on which the output
  is based is insufficient to distinguish regular mutexes and mutexes
  that protect rw-locks (which permit multiple readers or a single
  writer). Consequently, the output may appear to contain multiple rows
  for the same mutex.

  o count indicates how many times the mutex was requested.

  o spin_waits indicates how many times the spinlock had to run.

  o spin_rounds indicates the number of spinlock rounds. (spin_rounds
    divided by spin_waits provides the average round count.)

  o os_waits indicates the number of operating system waits. This
    occurs when the spinlock did not work (the mutex was not locked
    during the spinlock and it was necessary to yield to the operating
    system and wait).

  o os_yields indicates the number of times a the thread trying to lock
    a mutex gave up its timeslice and yielded to the operating system
    (on the presumption that permitting other threads to run will free
    the mutex so that it can be locked).

  o os_wait_times indicates the amount of time (in ms) spent in
    operating system waits, if the timed_mutexes system variable is 1
    (ON). If timed_mutexes is 0 (OFF), timing is disabled, so
    os_wait_times is 0. timed_mutexes is off by default.

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.

Use SHOW ENGINE PERFORMANCE_SCHEMA STATUS to inspect the internal
operation of the Performance Schema code:

mysql> SHOW ENGINE PERFORMANCE_SCHEMA STATUS\G
...
*************************** 3. row ***************************
  Type: performance_schema
  Name: events_waits_history.row_size
Status: 76
*************************** 4. row ***************************
  Type: performance_schema
  Name: events_waits_history.row_count
Status: 10000
*************************** 5. row ***************************
  Type: performance_schema
  Name: events_waits_history.memory
Status: 760000
...
*************************** 57. row ***************************
  Type: performance_schema
  Name: performance_schema.memory
Status: 26459600
...

The intent of this statement is to help the DBA to understand the
effects that different options have on memory requirements.

Name values consist of two parts, which name an internal buffer and an
attribute of the buffer, respectively:

o Internal buffers that are exposed as a table in the
  performance_schema database are named after the table. Examples:
  events_waits_history.row_size, mutex_instances.row_count.

o Internal buffers that are not exposed as a table are named within
  parentheses. Examples: (pfs_cond_class).row_size,
  (pfs_mutex_class).memory.

o Values that apply to the Performance Schema as a whole begin with
  performance_schema. Example: performance_schema.memory.

Attributes have these meanings:

o row_size cannot be changed. It is the size of the internal record
  used by the implementation.

o row_count can be changed depending on the configuration options.

o For a table, tbl_name.memory is the product of row_size multiplied by
  row_count. For the Performance Schema as a whole,
  performance_schema.memory is the sum of all the memory used (the sum
  of all other memory values).

In some cases, there is a direct relationship between a configuration
parameter and a SHOW ENGINE value. For example,
events_waits_history_long.row_count corresponds to
performance_schema_events_waits_history_long_size. In other cases, the
relationship is more complex. For example,
events_waits_history.row_count corresponds to
performance_schema_events_waits_history_size (the number of rows per
thread) multiplied by performance_schema_max_thread_instances ( the
number of threads).

If the server has the NDBCLUSTER storage engine enabled, SHOW ENGINE
NDB STATUS displays cluster status information such as the number of
connected data nodes, the cluster connectstring, and cluster binlog
epochs, as well as counts of various Cluster API objects created by the
MySQL Server when connected to the cluster. Sample output from this
statement is shown here:

mysql> SHOW ENGINE NDB STATUS;
+------------+-----------------------+--------------------------------------------------+
| Type       | Name                  | Status                                           |
+------------+-----------------------+--------------------------------------------------+
| ndbcluster | connection            | cluster_node_id=7,
  connected_host=192.168.0.103, connected_port=1186, number_of_data_nodes=4,
  number_of_ready_data_nodes=3, connect_count=0                                         |
| ndbcluster | NdbTransaction        | created=6, free=0, sizeof=212                    |
| ndbcluster | NdbOperation          | created=8, free=8, sizeof=660                    |
| ndbcluster | NdbIndexScanOperation | created=1, free=1, sizeof=744                    |
| ndbcluster | NdbIndexOperation     | created=0, free=0, sizeof=664                    |
| ndbcluster | NdbRecAttr            | created=1285, free=1285, sizeof=60               |
| ndbcluster | NdbApiSignal          | created=16, free=16, sizeof=136                  |
| ndbcluster | NdbLabel              | created=0, free=0, sizeof=196                    |
| ndbcluster | NdbBranch             | created=0, free=0, sizeof=24                     |
| ndbcluster | NdbSubroutine         | created=0, free=0, sizeof=68                     |
| ndbcluster | NdbCall               | created=0, free=0, sizeof=16                     |
| ndbcluster | NdbBlob               | created=1, free=1, sizeof=264                    |
| ndbcluster | NdbReceiver           | created=4, free=0, sizeof=68                     |
| ndbcluster | binlog                | latest_epoch=155467, latest_trans_epoch=148126,
  latest_received_binlog_epoch=0, latest_handled_binlog_epoch=0,
  latest_applied_binlog_epoch=0                                                         |
+------------+-----------------------+--------------------------------------------------+

The rows with connection and binlog in the Name column were added to
the output of this statement in MySQL 5.1. The Status column in each of
these rows provides information about the MySQL server's connection to
the cluster and about the cluster binary log's status, respectively.
The Status information is in the form of comma-delimited set of
name/value pairs.

URL: http://dev.mysql.com/doc/refman/5.5/en/show-engine.html

