innodb_log_file_size的大小设置将会影响
mysql数据库
的写入性能，若设置的太小，
会增加checkpoint写的次数，以下测试在MySQL5.7版本中的如何修改innodb_log_file_size
[root@endb local]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.9-log MySQL Community Server (GPL)
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Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
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Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show variables like '%innodb_log_file%';
+---------------------------+------------+
| Variable_name | Value |
+---------------------------+------------+
| innodb_log_file_size | 1073741824 |
| innodb_log_files_in_group | 2 |
+---------------------------+------------+
2 rows in set (0.00 sec)
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mysql> select 1073741824/1024/1024;
+----------------------+
| 1073741824/1024/1024 |
+----------------------+
| 1024.00000000 |
+----------------------+
1 row in set (0.00 sec)
这里确认innodb_fast_shutdown为1，这样在重启MySQL时，不会使用ib_logfile文件
mysql> show variables like '%shutdown%';
+-------------------------------------+-------+
| Variable_name | Value |
+-------------------------------------+-------+
| innodb_buffer_pool_dump_at_shutdown | ON |
| innodb_fast_shutdown | 1 |
+-------------------------------------+-------+
2 rows in set (0.00 sec)
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mysql> show variables like '%datadir%';
+---------------+--------------+
| Variable_name | Value |
+---------------+--------------+
| datadir | /home/mysql/ |
+---------------+--------------+
1 row in set (0.00 sec)
[root@endb local]# /etc/init.d/mysql stop
Shutting down MySQL...[ OK ]
[root@endb local]# grep innodb_log /etc/my.cnf
innodb_log_file_size = 512M
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[root@endb mysql]# cp ib_logfile* ..
[root@endb mysql]# ll ib_logfile*
-rw-r----- 1 mysql mysql 1073741824 Mar 3 15:03 ib_logfile0
-rw-r----- 1 mysql mysql 1073741824 Nov 25 16:09 ib_logfile1
[root@endb mysql]# ll -h ib_logfile*
-rw-r----- 1 mysql mysql 1.0G Mar 3 15:03 ib_logfile0
-rw-r----- 1 mysql mysql 1.0G Nov 25 16:09 ib_logfile1
www.nvzi91.cnmysql> show variables like '%innodb_log%';
+-----------------------------+-----------+
| Variable_name | Value |
+-----------------------------+-----------+
| innodb_log_buffer_size | 16777216 |
| innodb_log_checksums | ON |
| innodb_log_compressed_pages | ON |
| innodb_log_file_size | 536870912 |
| innodb_log_files_in_group | 2 |
| innodb_log_group_home_dir | ./ |
| innodb_log_write_ahead_size | 8192 |
+-----------------------------+-----------+
7 rows in set (0.00 sec)
[root@endb mysql]# ll -h ib_logfile*
-rw-r----- 1 mysql mysql 512M Mar 3 15:05 ib_logfile0
-rw-r----- 1 mysql mysql 512M Mar 3 15:05 ib_logfile1