MySQL 性能跟踪语句

MYSQL5.0家族提供的性能跟踪器确实很爽。
要注意两点。
1、不过版本要在5.0.37之后

手册上介绍：(SHOW PROFILES and SHOW PROFILE were added in MySQL 5.0.37. )
Important
Please note that the SHOW PROFILE and SHOW PROFILES functionality is part of the MySQL 5.0 Community Server only.
2、变量profiling是用户变量，每次都得重新启用。
以下是我做的一些实验。数据很明显，就不多解释了。

mysql> use test
Database changed
mysql> set profiling=1;
Query OK, 0 rows affected (0.00 sec)

mysql> show tables;
+----------------+

| Tables_in_test |
+----------------+

| bag_item |
| bag_user |
| score |
| t |
+----------------+

4 rows in set (0.03 sec)

mysql> select count(*) from t;
+----------+

| count(*) |
+----------+

| 2097152 |
+----------+

1 row in set (0.74 sec)

mysql> show profiles;
+----------+------------+------------------------+
| Query_ID | Duration   | Query                  |
+----------+------------+------------------------+
|        1 | 0.02717000 | show tables            |
|        2 | 0.74770100 | select count(*) from t |
+----------+------------+------------------------+
2 rows in set (0.00 sec)

mysql> show profile for query 2;
+--------------------------------+----------+
| Status                         | Duration |
+--------------------------------+----------+
| (initialization)               | 0.000004 |
| checking query cache for query | 0.000044 |
| Opening tables                 | 0.000012 |
| System lock                    | 0.000017 |
| Table lock                     | 0.00003  |
| init                           | 0.000013 |
| optimizing                     | 0.000008 |
| statistics                     | 0.000013 |
| preparing                      | 0.000011 |
| executing                      | 0.000006 |
| Sending data                   | 0.747313 |
| end                            | 0.000014 |
| query end                      | 0.000006 |
| storing result in query cache  | 0.000006 |
| freeing items                  | 0.000012 |
| closing tables                 | 0.000009 |
| logging slow query             | 0.000183 |
+--------------------------------+----------+
17 rows in set (0.00 sec)

mysql> show profile block io,cpu for query 2;
+--------------------------------+----------+----------+------------+--------------+---------------+
| Status                         | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out |
+--------------------------------+----------+----------+------------+--------------+---------------+
| (initialization)               | 0.000004 | 0        | 0          |            0 |             0 |
| checking query cache for query | 0.000044 | 0        | 0          |            0 |             0 |
| Opening tables                 | 0.000012 | 0        | 0          |            0 |             0 |
| System lock                    | 0.000017 | 0        | 0          |            0 |             0 |
| Table lock                     | 0.00003  | 0        | 0          |            0 |             0 |
| init                           | 0.000013 | 0        | 0          |            0 |             0 |
| optimizing                     | 0.000008 | 0        | 0          |            0 |             0 |
| statistics                     | 0.000013 | 0        | 0          |            0 |             0 |
| preparing                      | 0.000011 | 0        | 0          |            0 |             0 |
| executing                      | 0.000006 | 0        | 0          |            0 |             0 |
| Sending data                   | 0.747313 | 0.746887 | 0          |            0 |             0 |
| end                            | 0.000014 | 0        | 0          |            0 |             0 |
| query end                      | 0.000006 | 0        | 0          |            0 |             0 |
| storing result in query cache  | 0.000006 | 0        | 0          |            0 |             0 |
| freeing items                  | 0.000012 | 0        | 0          |            0 |             0 |
| closing tables                 | 0.000009 | 0        | 0          |            0 |             0 |
| logging slow query             | 0.000183 | 0        | 0          |            0 |             0 |
+--------------------------------+----------+----------+------------+--------------+---------------+
17 rows in set (0.00 sec)

mysql> insert into t(username) select username from t;
Query OK, 2097152 rows affected (34.17 sec)
Records: 2097152  Duplicates: 0  Warnings: 0

mysql> show profiles;
+----------+-------------+------------------------------------------------+
| Query_ID | Duration    | Query                                          |
+----------+-------------+------------------------------------------------+
|        1 |  0.02717000 | show tables                                    |
|        2 |  0.74770100 | select count(*) from t                         |
|        3 |  0.00004200 | show prifile for query 2                       |
|        4 | 34.30410100 | insert into t(username) select username from t |
+----------+-------------+------------------------------------------------+
4 rows in set (0.00 sec)

mysql> show profile cpu,block io,memory,swaps for query 4;
+------------------------------+-----------+-----------+------------+--------------+---------------+-------+
| Status                       | Duration  | CPU_user  | CPU_system | Block_ops_in | Block_ops_out | Swaps |
+------------------------------+-----------+-----------+------------+--------------+---------------+-------+
| (initialization)             | 0.000038  | 0         | 0          |            0 |             0 |     0 |
| checking permissions         | 0.000016  | 0         | 0          |            0 |             0 |     0 |
| Opening tables               | 0.000014  | 0         | 0          |            0 |             0 |     0 |
| System lock                  | 0.000007  | 0         | 0          |            0 |             0 |     0 |
| Table lock                   | 0.000013  | 0         | 0          |            0 |             0 |     0 |
| init                         | 0.000015  | 0         | 0          |            0 |             0 |     0 |
| optimizing                   | 0.000006  | 0         | 0          |            0 |             0 |     0 |
| statistics                   | 0.000012  | 0         | 0          |            0 |             0 |     0 |
| preparing                    | 0.000011  | 0         | 0          |            0 |             0 |     0 |
| Creating tmp table           | 0.000029  | 0         | 0          |            0 |             0 |     0 |
| executing                    | 0.000005  | 0         | 0          |            0 |             0 |     0 |
| Copying to tmp table         | 1.262877  | 1.24981   | 0.012998   |            0 |             0 |     0 |
| converting HEAP to MyISAM    | 0.384814  | 0.187971  | 0.19797    |            0 |             0 |     0 |
| Copying to tmp table on disk | 1.417069  | 1.203817  | 0.191971   |            0 |             0 |     0 |
| Sending data                 | 31.104185 | 13.965877 | 0.843872   |            0 |             0 |     0 |
| end                          | 0.000017  | 0         | 0          |            0 |             0 |     0 |
| removing tmp table           | 0.134872  | 0         | 0.029995   |            0 |             0 |     0 |
| end                          | 0.000026  | 0         | 0          |            0 |             0 |     0 |
| query end                    | 0.000006  | 0         | 0          |            0 |             0 |     0 |
| freeing items                | 0.000011  | 0         | 0          |            0 |             0 |     0 |
| closing tables               | 0.000009  | 0         | 0          |            0 |             0 |     0 |
| logging slow query           | 0.000049  | 0         | 0          |            0 |             0 |     0 |
+------------------------------+-----------+-----------+------------+--------------+---------------+-------+
22 rows in set (0.00 sec)

mysql> select count(*) from t;
+----------+
| count(*) |
+----------+
|  4194304 |
+----------+
1 row in set (1.51 sec)

mysql> show profiles;
+----------+-------------+------------------------------------------------+
| Query_ID | Duration    | Query                                          |
+----------+-------------+------------------------------------------------+
|        1 |  0.02717000 | show tables                                    |
|        2 |  0.74770100 | select count(*) from t                         |
|        3 |  0.00004200 | show prifile for query 2                       |
|        4 | 34.30410100 | insert into t(username) select username from t |
|        5 |  1.50563800 | select count(*) from t                         |
+----------+-------------+------------------------------------------------+
5 rows in set (0.00 sec)

mysql> show profile cpu,block io,memory,swaps,context switches,source for query 5;
+--------------------------------+----------+----------+------------+-------------------+---------------------+--------------+---------------+-------+---------------------------+---------------+-------------+
| Status                         | Duration | CPU_user | CPU_system | Context_voluntary | Context_involuntary | Block_ops_in | Block_ops_out | Swaps | Source_function           | Source_file   | Source_line |
+--------------------------------+----------+----------+------------+-------------------+---------------------+--------------+---------------+-------+---------------------------+---------------+-------------+
| (initialization) | 0.000004 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | send_result_to_client | sql_cache.cc | 1099 |
| checking query cache for query | 0.000048 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | open_tables               | sql_base.cc   |        2629 |
| Opening tables                 | 0.000011 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | mysql_lock_tables         | lock.cc       |         153 |
| System lock                    | 0.000007 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | mysql_lock_tables         | lock.cc       |         162 |
| Table lock                     | 0.000032 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | mysql_select              | sql_select.cc |        2242 |
| init                           | 0.000013 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | optimize                  | sql_select.cc |         745 |
| optimizing                     | 0.000008 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | optimize                  | sql_select.cc |         904 |
| statistics                     | 0.000013 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | optimize                  | sql_select.cc |         914 |
| preparing                      | 0.000011 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | exec                      | sql_select.cc |        1565 |
| executing                      | 0.000006 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | exec                      | sql_select.cc |        2083 |
| Sending data                   | 1.505401 | 1.504771 | 0          |                 3 |                   5 |            0 |             0 |     0 | mysql_select              | sql_select.cc |        2287 |
| end                            | 0.000015 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | mysql_execute_command     | sql_parse.cc  |        5122 |
| query end                      | 0.000005 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | query_cache_end_of_result | sql_cache.cc  |         729 |
| storing result in query cache  | 0.000007 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | mysql_parse               | sql_parse.cc  |        6116 |
| freeing items                  | 0.00001  | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | dispatch_command          | sql_parse.cc  |        2146 |
| closing tables                 | 0.000009 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | log_slow_statement        | sql_parse.cc  |        2204 |
| logging slow query             | 0.000038 | 0        | 0          |                 0 |                   0 |            0 |             0 |     0 | dispatch_command          | sql_parse.cc  |        2169 |
+--------------------------------+----------+----------+------------+-------------------+---------------------+--------------+---------------+-------+---------------------------+---------------+-------------+
17 rows in set (0.00 sec)
mysql> update t set username = 'waill';
Query OK, 4194304 rows affected (44.82 sec)
Rows matched: 4194304  Changed: 4194304  Warnings: 0

mysql> show profiles;
+----------+-------------+------------------------------------------------+
| Query_ID | Duration    | Query                                          |
+----------+-------------+------------------------------------------------+
|        1 |  0.02717000 | show tables                                    |
|        2 |  0.74770100 | select count(*) from t                         |
|        3 |  0.00004200 | show prifile for query 2                       |
|        4 | 34.30410100 | insert into t(username) select username from t |
|        5 |  1.50563800 | select count(*) from t                         |
|        6 | 44.82054700 | update t set username = 'waill'                |
+----------+-------------+------------------------------------------------+
6 rows in set (0.00 sec)

mysql> show profile cpu,block io,memory,swaps,context switches,source for query 6;
+----------------------+-----------+-----------+------------+-------------------+---------------------+--------------+---------------+-------+-----------------------+---------------+-------------+
| Status               | Duration  | CPU_user  | CPU_system | Context_voluntary | Context_involuntary | Block_ops_in | Block_ops_out | Swaps | Source_function       | Source_file   | Source_line |
+----------------------+-----------+-----------+------------+-------------------+---------------------+--------------+---------------+-------+-----------------------+---------------+-------------+
| (initialization)     | 0.000035  | 0         | 0          |                 0 |                   0 |            0 |             0 |     0 | check_access          | sql_parse.cc  |        5306 |
| checking permissions | 0.000011  | 0         | 0          |                 0 |                   0 |            0 |             0 |     0 | open_tables           | sql_base.cc   |        2629 |
| Opening tables       | 0.000011  | 0         | 0          |                 0 |                   0 |            0 |             0 |     0 | mysql_lock_tables     | lock.cc       |         153 |
| System lock          | 0.000007  | 0         | 0          |                 0 |                   0 |            0 |             0 |     0 | mysql_lock_tables     | lock.cc       |         162 |
| Table lock           | 0.000008  | 0         | 0          |                 0 |                   0 |            0 |             0 |     0 | mysql_update          | sql_update.cc |         167 |
| init                 | 0.000021  | 0         | 0          |                 0 |                   0 |            0 |             0 |     0 | mysql_update          | sql_update.cc |         429 |
| Updating             | 44.514679 | 27.976747 | 2.818571   |              9949 |                1584 |            0 |             0 |     0 | mysql_update          | sql_update.cc |         560 |
| end                  | 0.305671  | 0.028996  | 0.023997   |                43 |                  18 |            0 |             0 |     0 | mysql_execute_command | sql_parse.cc  |        5122 |
| query end            | 0.000026  | 0         | 0          |                 0 |                   0 |            0 |             0 |     0 | mysql_parse           | sql_parse.cc  |        6116 |
| freeing items        | 0.000016  | 0         | 0          |                 0 |                   0 |            0 |             0 |     0 | dispatch_command      | sql_parse.cc  |        2146 |
| closing tables       | 0.000012  | 0         | 0          |                 0 |                   0 |            0 |             0 |     0 | log_slow_statement    | sql_parse.cc  |        2204 |
| logging slow query   | 0.00005   | 0         | 0          |                 0 |                   0 |            0 |             0 |     0 | dispatch_command      | sql_parse.cc  |        2169 |
+----------------------+-----------+-----------+------------+-------------------+---------------------+--------------+---------------+-------+-----------------------+---------------+-------------+
12 rows in set (0.00 sec)

问题：
如果sql的语句的字符长度超过300个字符，后面的字符就显示不了，也就是query字段300个字符后的显示不了。
重现：
脚本：

<?php
$row =$db->query("show profiles");
$string = '<hr />';
while ($r = $db->fetch_array($row)){
    $string .="<div style='font-size:11px;padding:12px;'>查询ID：{$r['Query_ID']}<div>查询耗时：{$r['Duration']}</div><div style='color:blue;'>查询语句：<br />{$r['Query']}</div></div>";
}
$string .='<hr /><br />';
echo $string;
?>

结果：
查询ID：1
查询耗时：0.00052150
查询语句：

SELECT f.fid,f.childid,f.fup,f.type,f.logo,f.name, f.descrip,f.forumadmin,f.across,f.allowhtm,f.password,f.allowvisit,f.f_type,f.cms,f.showsub,fd.tpost,fd.topic,fd.article,fd.subtopic,fd.top1,fd.lastpost FROM pw_forums f LEFT JOIN pw_forumdata fd USING(fid) WHERE f.ifsub='0' AND f.cms!='1' ORDER BY

查询ID：2
查询耗时：0.01725150
查询语句：
SELECT * FROM pw_bbsinfo WHERE id=1

sql语句超过300字符。

如果：
Query Error: show profiles\G

The URL Is:
http://localhost/aaron/phpwind/index.php?

MySQL Server Error:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '\G' at line 1 ( 1064 )

You Can Get Help In:
http://www.phpwind.net
解决方案：

--- 1.3/sql/sql_profile.cc    2007-02-22 09:56:27 -05:00
+++ 1.4/sql/sql_profile.cc    2007-02-22 09:56:27 -05:00
@@ -19,6 +19,7 @@
#include "my_sys.h"

#define TIME_FLOAT_DIGITS 7
+#define MAX_QUERY_LENGTH 300

要修改这儿才可以多于300，增加 max_allowed_packet 不行的