http://dev.mysql.com/doc/refman/5.0/en/show-profiles.html
13.7.5.29. SHOW PROFILES
Syntax
SHOW PROFILE [type
[,type
] ... ] [FOR QUERYn
] [LIMITrow_count
[OFFSEToffset
]]type
: ALL | BLOCK IO | CONTEXT SWITCHES | CPU | IPC | MEMORY | PAGE FAULTS | SOURCE | SWAPS
The
SHOW PROFILES
and
SHOW PROFILE
statements display profiling information that indicates resource usage for statements executed during the course of the current session.
Profiling is controlled by the
profiling
session variable, which has a default value of 0 (OFF
). Profiling is enabled by setting
profiling
to 1 or ON
:
mysql> SET profiling = 1;
SHOW PROFILES
displays a list of the most recent statements sent to the master. The size of the list is controlled
by the
profiling_history_size
session variable, which has a default value of 15. The maximum value is 100. Setting the value to 0 has the practical effect of disabling profiling.
All statements are profiled except
SHOW PROFILES
and
SHOW PROFILE
, so you will find neither of those statements in the profile list. Malformed statements are profiled. For example,
SHOW PROFILING
is an illegal statement, and a syntax error occurs if you try to execute it, but it will show up in the profiling list.
SHOW PROFILE
displays detailed information about a single statement. Without the
FOR QUERY
clause, the output pertains to the most recently executed statement. If
n
FOR QUERY
is included,
n
SHOW PROFILE
displays information for statement
n
. The values of n
correspond to the
Query_ID
values displayed by
SHOW PROFILES
.
The LIMIT
clause may be given to limit the output to
row_count
row_count
rows. If
LIMIT
is given, OFFSET
may be added to begin the output
offset
offset
rows into the full set of rows.
By default,
SHOW PROFILE
displays Status
and
Duration
columns. The Status
values are like the
State
values displayed by
SHOW PROCESSLIST
, although there might be some minor differences in interpretion for the two statements for some status values (see
Section 8.10, “Examining Thread Information”).
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)
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.
SHOW PROFILES
and
SHOW PROFILE
were added in MySQL 5.0.37.
You can also get profiling information from the
PROFILING
table in INFORMATION_SCHEMA
. See
Section 19.7, “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 DURATION FROM INFORMATION_SCHEMA.PROFILING WHERE QUERY_ID = 2 ORDER BY SEQ;
Please note that the
SHOW PROFILE
and
SHOW PROFILES
functionality is part of the MySQL 5.0 Community Server only.