InnoDB Infrastructure Cleanup

To shrink ibdata1 once and for all you must do the following:


  1. Dump (e.g., with mysqldump) all databases into a .sql text file (SQLData.sql is used below)

  1. Drop all databases (except for mysql and information_schema) CAVEAT : As a precaution, please run this script to make absolutely sure you have all user grants in place:

 mkdir /var/lib/mysql_grants
  cp /var/lib/mysql/mysql/* /var/lib/mysql_grants/.
  chown -R mysql:mysql /var/lib/mysql_grants

  1. Login to mysql and run SET GLOBAL innodb_fast_shutdown = 0; (This will completely flush all remaining transactional changes from ib_logfile0 and ib_logfile1)

  1. Shutdown MySQL

  1. Add the following lines to /etc/my.cnf (or my.ini on Windows)

 [mysqld]
  innodb_file_per_table
  innodb_flush_method=O_DIRECT
  innodb_log_file_size=1G
  innodb_buffer_pool_size=4G

(Sidenote: Whatever your set for innodb_buffer_pool_size, make sure innodb_log_file_size is 25% of innodb_buffer_pool_size.

Also: innodb_flush_method=O_DIRECT is not available on Windows)

  1. Delete ibdata* and ib_logfile*, Optionally, you can remove all folders in /var/lib/mysql, except /var/lib/mysql/mysql.

  1. Start MySQL (This will recreate ibdata1 [10MB by default] and ib_logfile0 and ib_logfile1 at 1G each).

  1. Import SQLData.sql

Now, ibdata1 will still grow but only contain table metadata because each InnoDB table will exist outside of ibdata1. ibdata1 will no longer contain InnoDB data and indexes for other tables.


For example, suppose you have an InnoDB table named mydb.mytable. If you look in /var/lib/mysql/mydb, you will see two files representing the table:


mytable.frm (Storage Engine Header)
mytable.ibd (Table Data and Indexes)

With the innodb_file_per_table option in /etc/my.cnf, you can run OPTIMIZE TABLE mydb.mytable and the file /var/lib/mysql/mydb/mytable.ibd will actually shrink.


I have done this many times in my career as a MySQL DBA. In fact, the first time I did this, I shrank a 50GB ibdata1 file down to only 500MB!


Give it a try. If you have further questions on this, just ask. Trust me; this will work in the short term as well as over the long haul.

CAVEAT


At Step 6, if mysql cannot restart because of the mysql schema begin dropped, look back at Step 2. You made the physical copy of the mysql schema. You can restore it as follows:


 mkdir /var/lib/mysql/mysql
cp /var/lib/mysql_grants/* /var/lib/mysql/mysql
chown -R mysql:mysql /var/lib/mysql/mysql

Go back to Step 6 and continue




Source: Clean a mysql InnoDB storage engine?