Linux – How to export the privileges from MySQL and then import to a new server

database-administrationdebianlinuxMySQLmysql-replication

I know how to export/import the databases using mysqldump & that's fine but how do I get the privileges into the new server.

For extra points, there are a couple of existing databases on the new one already, how do I import the old servers privileges without nuking the couple existing of ones.

Old server: 5.0.67-community

New server: 5.0.51a-24+lenny1

EDIT: I've got a dump of the db 'mysql' from the Old Server & now want to know the proper way to merge with the 'mysql' db on the New Server.

I tried a straight 'Import' using phpMyAdmin and ended up with an error regarding a duplicate (one that I've already migrated manually).

Anyone got an elegant way of merging the two 'mysql' databases?

Best Answer

Do not mess with the mysql db. There is a lot more going on there than just the users table. Your best bet is the "SHOW GRANTS FOR" command. I have a lot of CLI maintenance aliases and functions in my .bashrc (actually my .bash_aliases that I source in my .bashrc). This function:

mygrants()
{
  mysql -B -N $@ -e "SELECT DISTINCT CONCAT(
    'SHOW GRANTS FOR \'', user, '\'@\'', host, '\';'
    ) AS query FROM mysql.user" | \
  mysql $@ | \
  sed 's/\(GRANT .*\)/\1;/;s/^\(Grants for .*\)/## \1 ##/;/##/{x;p;x;}'
}

The first mysql command uses SQL to generate valid SQL which is piped to the second mysql command. The output is then piped through sed to add pretty comments.

The $@ in the command will allow you to call it as: mygrants --host=prod-db1 --user=admin --password=secret

You can use your full unix tool kit on this like so:

mygrants --host=prod-db1 --user=admin --password=secret | grep rails_admin | mysql --host=staging-db1 --user=admin --password=secret

That is THE right way to move users. Your MySQL ACL is modified with pure SQL.

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