MySQLinsanity! This document provides an overview of Stanley Huang's MySQL performance tuning experience and expertise. It begins with introductions and background on Stanley Huang. It then discusses the typical phases of MySQL performance tuning projects, including SQL tuning and RDBMS tuning. Specific tips are provided around topics like slow query logging, index usage, partitioning, and server configuration. The document concludes with an invitation for questions.

1. MySQLinsanity!
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2. Topic
▪ Who am I?
▪ MySQL performance tuning experience sharing.
▪ Q & A.
2

3. Who am I?
▪ Stanley Huang (黃偉倫)
▪ My email
▪ wenlien1001@gmail.com
▪ My Blog
▪ http://stanley-huang.blogspot.com
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4. MySQL performance tuning experience
sharing
▪ What happened to the product?
▪ Too many data and have query performance issue
▪ Performance tuning phases
1. SQL tuning
▪ Over 90%, bad SQLs make great impact on
performance
▪ Over 90%, do not using the correct index(es) in bad
SQLs
2. RDBMS tuning
4

5. MySQL SQL tuning(1/2)
▪ Enable slow query log and find out the top 10 slow
queries
▪ Add two settings in my.cnf
▪ log-slow-queries ## default off
▪ long-query-time=5 ## default 10
▪ [data folder]/[host name]-slow.log
5

6. MySQL SQL tuning(2/2)
▪ Perform full-text search on InnoDB
(select … like ‘*pattern*’)
1. Change storage engine from InnoDB to MyISAM
2. Hybrid storage engine, create a new MyISAM table and move
data need to be full-text search from InnoDB to MyISAM
▪ Too many indexes
1. Create more indexes won’t enhance performance but impact on
writing.
2. (Suggestion) Don’t create more than 5 indexes on one table.
InnoDB in MySQL 5.6 has supported full-text search
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7. Useful Tips For Networking System
1. IP Support
2. Mac Support
7

8. IP address support
 Build In Function: inet_ntoa()/inet_aton()
mysql> CREATE TABLE testIP (
ip_int int unsigned DEFAULT NULL,
ip_char char(15) DEFAULT NULL,
index ip_int (ip_int),
index ip_char (ip_char)
) ENGINE=InnoDB;
mysql> insert into testIP valuse(inet_aton('216.18.50.126'),'216.18.50.126');
mysql> select inet_ntoa(ip_int),ip_char from testIP;
+-------------------+---------------+
| inet_ntoa(ip_int) | ip_char |
+-------------------+---------------+
| 216.18.50.126 | 216.18.50.126 |
+-------------------+---------------+
8

9. Execution Plain
mysql> explain select * from testIP where ip_char='216.18.50.126';
+----+-------------+--------+------+---------------+---------+---------+-------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+--------+------+---------------+---------+---------+-------+------+-------------+
| 1 | SIMPLE | testIP | ref | ip_char | ip_char | 16 | const | 1 | Using where |
+----+-------------+--------+------+---------------+---------+---------+-------+------+-------------+
mysql> explain select * from testIP where ip_int=inet_aton('216.18.50.126');
+----+-------------+--------+------+---------------+--------+---------+-------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+--------+------+---------------+--------+---------+-------+------+-------------+
| 1 | SIMPLE | testIP | ref | ip_int | ip_int | 5 | const | 1 | Using where |
+----+-------------+--------+------+---------------+--------+---------+-------+------+-------------+
9

10. Mac address support??
 Build In Function: hex()
mysql> create table testMAC(mac_bit bit(48), mac_char char(17),
index(mac_bit), index(mac_char));
mysql> insert into testMAC values (x'00241DDC5548', '00:24:1D:DC:55:48');
mysql> select hex(mac_bit), mac_char from testMAC;
+--------------+-------------------+
| hex(mac_bit) | mac_char |
+--------------+-------------------+
| 241DDC5548 | 00:24:1D:DC:55:48 |
+--------------+-------------------+
Build In Function seems not enough~
1. create MySQL stored function
2. create UDF (User Define Function)
10

11. Execution Plain
mysql> explain select hex(mac_bit), mac_char from testMAC where
mac_char='00:24:1D:DC:55:48';
+----+-------------+----------+------+---------------+----------+---------+-------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+----------+------+---------------+----------+---------+-------+------+-------------+
| 1 | SIMPLE | testMAC2 | ref | mac_char | mac_char | 18 | const | 1 | Using where |
+----+-------------+----------+------+---------------+----------+---------+-------+------+-------------+
mysql> explain select hex(mac_bit), mac_char from testMAC where mac_bit=x'00241DDC5548';
+----+-------------+----------+------+---------------+---------+---------+-------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+----------+------+---------------+---------+---------+-------+------+-------------+
| 1 | SIMPLE | testMAC2 | ref | mac_bit | mac_bit | 7 | const | 1 | Using where |
+----+-------------+----------+------+---------------+---------+---------+-------+------+-------------+
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12. Stored Function for MAC address
## create stored function ether_atob(), from ascii to bit
## must define "deterministic", or explain will not use index
delimiter //
drop function if exists ether_atob//
create function ether_atob(sAscii char(17))
returns bit(48)
deterministic
Begin
declare bReturn bit(48);
set bReturn=unhex(replace(sAscii,':',''));
return bReturn;
end//
delimiter ;
12

13. Stored Function for MAC address
(cont.)
## create stored function ether_btoa(), from bit to ascii
## must define "deterministic", or explain will not use index
delimiter //
drop function if exists ether_btoa//
create function ether_btoa(sBit bit(48))
returns char(17)
deterministic
begin
declare sReturn char(17);
set sReturn=lpad(hex(sBit),12,'0');
set sReturn=concat_ws(':', substr(sReturn,1,2), substr(sReturn,3,2),
substr(sReturn,5,2),
substr(sReturn,7,2), substr(sReturn,9,2), substr(sReturn,11,2));
return sReturn;
end//
delimiter ;
13

14. Stored Function for MAC address
(cont.)
mysql> create table ether_table (b bit(48), a char(17), index(b), index(a));
Query OK, 0 rows affected (0.67 sec)
mysql> insert into ether_table values
(ether_atob('00:CD:EF:00:CD:EF'),'00:CD:EF:00:CD:EF');
Query OK, 1 row affected (0.01 sec)
mysql> select ether_btoa(b), a from ether_table
where b=ether_atob('00:CD:EF:00:CD:EF');
+----------------+-------------------+
| ether_btoa(b) | a |
+----------------+-------------------+
| 00:CD:EF:00:CD:EF | 00:CD:EF:00:CD:EF |
+----------------+-------------------+
1 rows in set (0.01 sec )
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15. Stored Function for MAC address
(cont.)
mysql> explain select ether_btoa(b), a from ether_table where
b=ether_atob('00:CD:EF:00:CD:EF');
+----+-------------+-------------+------+---------------+------+---------+-------+------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+----+-------------+-------------+------+---------------+------+---------+-------+------+-------------+
| 1 | SIMPLE | ether_table | ref | b |b |7 | const | 1 | Using where |
+----+-------------+-------------+------+---------------+------+---------+-------+------+-------------+
1 row in set (0.00 sec)
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16. Create UDF
▪ http://stanley-huang.blogspot.com/2010/03/level-3-
create-udf-for-storing-mac.html
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17. Using UDF on MySQL Database
Make sure your MySQL supports UDF.
mysql> create function lib_mysqludf_log_info returns string soname
'lib_mysqludf_log.so';
ERROR 1126 (HY000): Can't open shared library 'lib_mysqludf_log.so' (errno:
0 feature disabled)
17

18. Compile MySQL with UDF enable
1. Download source code
2. # ./configure --with-mysqld-ldflags=--rdynamic
3. # gcc -shared -o ./udf_example.so ./udf_example.c -
I/usr/local/include/mysql -fPIC
4. # cp ./udf_example.so /usr/local/mysql/lib/mysql/plugin
5. mysql> CREATE FUNCTION metaphon RETURNS STRING
SONAME 'udf_example.so';
ERROR 1126 (HY000): Can't open shared library 'udf_example.so'
(errno: 22 /usr/local/lib/mysql/plugin/udf_example.so: cannot
restore segment prot after reloc: Permission denied)
6. # chcon -t texrel_shlib_t /usr/local/lib/mysql/plugin/udf_example.so
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19. Characters of Stored Function, UDF
and Native Function
Method Speed Language Development Maintenance
Stored slow SQL ~minutes easy
Function (for small
functions)
UDF fast C ~hour hard
Native fast C Major pain hard
Function
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20. Compare with UDF and Stored
Functions
Reference: Roland Bouman's blog
http://rpbouman.blogspot.com/2008/03/
udfs-at-mysql-users-conference.html
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21. MySQL performance tuning
▪ Separate disk I/O
▪ Separate disk I/O of bin log files and data files to different disks
▪ MyISAM configuration
▪ key_buffer_size=128M # default is 8M
▪ bulk_insert_buffer_size=4194304 # default is 8M
▪ InnoDB configuration
▪ innodb_buffer_pool_size=32M # default
▪ 8Minnodb_log_buffer_size=8M # default 1M
▪ Prevent large single large file of InnoDB tablespace
▪ innodb_file_per_table
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22. MySQL upgrade from 5.0 to 5.1
▪ In internal tests, MySQL 5.1 demonstrates, on average, a 15% gain
in total performance over MySQL 5.0. (There really is the free lunch)
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23. Partitioning Sample SQL
mysql> CREATE TABLE test_partition_np
-> ( c1 int default NULL,
-> c2 varchar(30) default NULL,
-> c3 date default NULL
-> ) engine=InnoDB;
Query OK, 0 rows affected (0.00 sec)
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24. What's wrong with “my” SQL
mysql> select count(1) from test_partition_wp where year(c3)=1995;
+----------+
| count(1) |
+----------+
| 47358 |
+----------+
1 row in set (0.58 sec)
mysql> select count(1) from test_partition_np where year(c3)=1995;
+----------+
| count(1) |
+----------+
| 47358 |
+----------+
1 row in set (0.53 sec) -- Faster then partition table, why??
24

25. Execution Plan
mysql> explain partitions select count(1) from test_partition_wp where
year(c3)=1995G
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: test_partition_wp
partitions: p0,p1,p2,p3,p4,p5,p6,p7,p8,p9,p10,p11
type: ALL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 12006556
Extra: Using where
1 row in set (0.00 sec)
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26. The correct SQL
mysql> select count(1) from test_partition_wp where c3 between '1995/01/01'
and '1995/12/31';
+----------+
| count(1) |
+----------+
| 47358 |
+----------+
1 row in set (0.04 sec) -- That's what I want!!
mysql> select count(1) from test_partition_np where c3 between '1995/01/01' and
'1995/12/31';
+----------+
| count(1) |
+----------+
| 47358 |
+----------+
1 row in set (0.62 sec)
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27. Execution Plan
mysql> explain partitions select count(1) from test_partition_wp where c3
between '1995/01/01' and '1995/12/31'G
*************************** 1. row ***************************
id: 1
select_type: SIMPLE
table: test_partition_wp
partitions: p1
type: ALL
possible_keys: NULL
key: NULL
key_len: NULL
ref: NULL
rows: 12006556
Extra: Using where
1 row in set (0.00 sec)
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28. Performance Enhancement With Table
Partitioning
After we use partition on the large tables, the performance raise 11-45% up.
1. 5.1-partition 377.4146 tableA
5.1 687.4756 tableA
(687.4756-377.4146) / 687.4756 = 0.45
2. 5.1-partition 171.7333 tableB
5.1 193.9878 tableB
(193.9878-171.7333) / 193.9878 = 0.11
3. 5.1-partition 22.0741 tableC
5.1 34.4792 tableC
(34.4792-22.0741) / 34.4792 = 0.36
4. 5.1-partition 1.8519 tableD
5.1 3.3750 tableD
(3.3750-1.8519) / 3.3750 = 0.45
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29. MySQL Performance Tips Summary
▪ Use EXPLAIN to profile the query.
▪ Always have slow query log.
▪ Avoid using wildcards at the start of LIKE queries.
▪ Isolate the workloads.
▪ Using data partitions..
▪ Don’t duplicate indexes.
▪ Use INET_ATON and INET_NTOA.
▪ Hire a MySQL Certified DBA.
http://forge.mysql.com/wiki/Top10SQLPerformanceTips
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30. Q&A
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