How to shrink/purge ibdata1 file in MySQL
I am using MySQL in localhost as a "query tool" for performing statistics in R, that is, everytime I run a R script, I create a new database (A), create a new table (B), import the data into B, submit a query to get what I need, and then I drop B and drop A.
It's working fine for me, but I realize that the ibdata file size is increasing rapidly, I stored nothing in MySQL, but the ibdata1 file already exceeded 100 MB.
I am using more or less default MySQL setting for the setup, is there a way for I can automatically shrink/purge the ibdata1 file after a fixed period of time?
1Answer
That ibdata1 isn't shrinking is a particularly annoying feature of MySQL. The ibdata1 file can´t actually be shrunk unless you delete all databases, remove the files and reload a dump.
But you can configure MySQL so that each table, including its indexes, is stored as a separate file. In that way ibdata1 will not grow as large.
It was a while ago I did this. However, to setup your server to use separate files for each table you need to change my.cnf in order to enable this:
[mysqld]
innodb_file_per_table
http://dev.mysql.com/doc/refman/5.5/en/innodb-multiple-tablespaces.html
As you want to reclaim the space from ibdata1 you actually have to delete the file:
- Do a
mysqldumpof all databases, procedures, triggers etc except themysqlandperformance_schemadatabases - Drop all databases except the above 2 databases
- Stop mysql
- Delete
ibdata1andib_logfiles - Start mysql
- Restore from dump
When you start MySQL in step 5 the ibdata1 and ib_log files will be recreated.
Now you're fit to go. When you create a new database for analysis, the tables will be located in separate ibd* files, not in ibdata1. As you usually drop the database soon after, the ibd* files will be deleted.
http://dev.mysql.com/doc/refman/5.1/en/drop-database.html
You have probably seen this:
http://bugs.mysql.com/bug.php?id=1341
By using the command ALTER TABLE <tablename> ENGINE=innodb or OPTIMIZE TABLE <tablename> one can extract data and index pages from ibdata1 to separate files. However, ibdata1 will not shrink unless you do the steps above.
- answered 8 years ago
- G John
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