MySQL: Converting all tables in all databases from MyISAM to InnoDB

From lxadm | Linux administration tips, tutorials, HOWTOs and articles
Jump to: navigation, search

With MySQL, for most use cases, InnoDB is a much better database engine than MyISAM.

If you have plenty of databases with tables in MyISAM format which you'd like to convert to InnoDB, here is a bash script which will do it.

The script only converts MyISAM tables, and will not re-convert already existing InnoDB tables.

Please note that it may take long to convert very large tables, so plan your maintenance time accordingly.

Usage:

  • if you would like to convert all database, please uncomment DATABASES="ALL" line; otherwise, adjust DATABASES variable to contain all databases in which you would like to convert the tables to InnoDB.
  • the script assumes your password is stored in ~./my.cnf - if it's not the case, please uncomment and set MYSQL_PASS variable and uncomment the other MYSQL_COMMAND (the one which uses --password="$MYSQL_PASS"); please note that mysql will output "Warning: Using a password on the command line interface can be insecure" in such case)
#!/bin/bash

# Converts all MyISAM tables in all databases to InnoDB


DATABASES="db1 db2"     # Convert databases db1 and db2 only

#DATABASES="ALL"         # Convert all databases

MYSQL_USER=root
# Uncomment if you're not using ~/.my.cnf file (will receive "Warning: Using a password on the command line interface can be insecure" warnings)
#MYSQL_PASS='some-secret-password'
MYSQL_HOST=localhost


### no need to change anything below
# bail out on undefined variables
set -u

# mysql command we will use
MYSQL_COMMAND="mysql -s -u "$MYSQL_USER" -h $MYSQL_HOST"
# Uncomment if you're not using ~/.my.cnf file (will receive "Warning: Using a password on the command line interface can be insecure" warnings)
#MYSQL_COMMAND="mysql -s -u "$MYSQL_USER" --password="$MYSQL_PASS" -h $MYSQL_HOST"

# get a list of databases if we want to convert all databases
if [ "$DATABASES" == "ALL" ] ; then
    DATABASES=$(echo "SHOW DATABASES" | $MYSQL_COMMAND | egrep -v '(performance_schema|information_schema|mysql)')
fi


for DATABASE in $DATABASES ; do
    echo Converting $DATABASE
    # Check if the table is MyISAM (we don't want to convert InnoDB tables over and over again)
    TABLES=$(echo "SELECT TABLE_NAME FROM information_schema.TABLES where TABLE_SCHEMA = '$DATABASE' and ENGINE = 'MyISAM'" | $MYSQL_COMMAND)
    for TABLE in $TABLES ; do
        echo Converting MyISAM $TABLE to InnoDB
        echo "ALTER TABLE $TABLE ENGINE = INNODB" | $MYSQL_COMMAND $DATABASE
    done
    if [ "x$TABLES" = "x" ] ; then
        echo No MyISAM tables found in $DATABASE database
    fi
    echo
done