show profile 分析性能

SHOW PROFILE [type [, type] ... ]    [FOR QUERY n]    [LIMIT row_count [OFFSET offset]]type:    ALL  | BLOCK IO  | CONTEXT SWITCHES  | CPU  | IPC  | MEMORY  | PAGE FAULTS  | SOURCE
  | SWAPS
Profiling is controlled by the profiling session variable, which has a default value of 0 (OFF). Profiling is enabled by setting profiling to 1 orON:
mysql> SET profiling = 1;
Optional type values may be specified to display specific additional types of information:
ALL displays all information
BLOCK IO displays counts for block input and output operations
CONTEXT SWITCHES displays counts for voluntary and involuntary context switches
CPU displays user and system CPU usage times
IPC displays counts for messages sent and received
MEMORY is not currently implemented
PAGE FAULTS displays counts for major and minor page faults
SOURCE displays the names of functions from the source code, together with the name and line number of the file in which the function occurs
SWAPS displays swap counts
Profiling is enabled per session. When a session ends, its profiling information is lost.
mysql> SELECT @@profiling;+-------------+| @@profiling |+-------------+|           0 |+-------------+1 row in set (0.00 sec)mysql> SET profiling = 1;Query OK, 0 rows affected (0.00 sec)mysql> DROP TABLE IF EXISTS t1;Query OK, 0 rows affected, 1 warning (0.00 sec)mysql> CREATE TABLE T1 (id INT);Query OK, 0 rows affected (0.01 sec)mysql> SHOW PROFILES;+----------+----------+--------------------------+| Query_ID | Duration | Query                    |+----------+----------+--------------------------+|        0 | 0.000088 | SET PROFILING = 1        ||        1 | 0.000136 | DROP TABLE IF EXISTS t1  ||        2 | 0.011947 | CREATE TABLE t1 (id INT) |+----------+----------+--------------------------+3 rows in set (0.00 sec)mysql> SHOW PROFILE;+----------------------+----------+| Status               | Duration |+----------------------+----------+| checking permissions | 0.000040 || creating table       | 0.000056 || After create         | 0.011363 || query end            | 0.000375 || freeing items        | 0.000089 || logging slow query   | 0.000019 || cleaning up          | 0.000005 |+----------------------+----------+7 rows in set (0.00 sec)mysql> SHOW PROFILE FOR QUERY 1;+--------------------+----------+| Status             | Duration |+--------------------+----------+| query end          | 0.000107 || freeing items      | 0.000008 || logging slow query | 0.000015 || cleaning up        | 0.000006 |+--------------------+----------+4 rows in set (0.00 sec)mysql> SHOW PROFILE CPU FOR QUERY 2;+----------------------+----------+----------+------------+| Status               | Duration | CPU_user | CPU_system |+----------------------+----------+----------+------------+| checking permissions | 0.000040 | 0.000038 |   0.000002 || creating table       | 0.000056 | 0.000028 |   0.000028 || After create         | 0.011363 | 0.000217 |   0.001571 || query end            | 0.000375 | 0.000013 |   0.000028 || freeing items        | 0.000089 | 0.000010 |   0.000014 || logging slow query   | 0.000019 | 0.000009 |   0.000010 || cleaning up          | 0.000005 | 0.000003 |   0.000002 |+----------------------+----------+----------+------------+7 rows in set (0.00 sec)
Note
Profiling is only partially functional on some architectures. For values that depend on the getrusage() system call,NULL is returned on systems such as Windows that do not support the call. In addition, profiling is per process and not per thread. This means that activity on threads within the server other than your own may affect the timing information that you see.
You can also get profiling information from the PROFILING table in INFORMATION_SCHEMA. See Section 22.18, “The INFORMATION_SCHEMA PROFILING Table”. For example, the following queries produce the same result:
SHOW PROFILE FOR QUERY 2;SELECT STATE, FORMAT(DURATION, 6) AS DURATIONFROM INFORMATION_SCHEMA.PROFILINGWHERE QUERY_ID = 2 ORDER BY SEQ;