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?
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. According to Bill Karwin's comment this is enabled by default as of version 5.6.6 of MySQL.
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=1
https://dev.mysql.com/doc/refman/5.6/en/innodb-file-per-table-tablespaces.html
As you want to reclaim the space from ibdata1
you actually have to delete the file:
mysqldump
of all databases, procedures, triggers etc except the mysql
and performance_schema
databases ibdata1
and ib_log
filesWhen 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.
Regarding the information_schema
, that is not necessary nor possible to drop. It is in fact just a bunch of read-only views, not tables. And there are no files associated with the them, not even a database directory. The informations_schema
is using the memory db-engine and is dropped and regenerated upon stop/restart of mysqld. See https://dev.mysql.com/doc/refman/5.7/en/information-schema.html.
Adding to John P's answer,
For a linux system, steps 1-6 can be accomplished with these commands:
mysqldump -u [username] -p[root_password] [database_name] > dumpfilename.sql
mysqladmin -u [username] -p[root_password] drop [database_name]
sudo /etc/init.d/mysqld stop
sudo rm /var/lib/mysql/ibdata1
sudo rm /var/lib/mysql/ib_logfile*
sudo /etc/init.d/mysqld start
mysqladmin -u [username] -p[root_password] create [database_name]
mysql -u [username] -p[root_password] [database_name] < dumpfilename.sql
Warning: these instructions will cause you to lose other databases if you have other databases on this mysql instance. Make sure that steps 1,2 and 6,7 are modified to cover all databases you wish to keep.
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