Solution when mysql stops working on mac (Rails project running)

After a long time using local mysql, it stopped working

When I used local mysql in the rails project for the first time in a while, mysql stopped working. The solution is described below.

For the time being, delete all the existing mysql

The data will disappear, but let's reinsert it with seed data. As a result, it is fast. If the old mysql is bad, it will take a lot of time to resolve it, so if you do not start mysql with docker and connect, let's delete mysql with brain death.

--How to delete community edition mysql

rm -rf ~/Library/PreferencePanes/My*
sudo rm /usr/local/mysql
sudo rm -rf /usr/local/mysql*
sudo rm -rf /Library/StartupItems/MySQLCOM
sudo rm -rf /Library/PreferencePanes/My*
sudo rm -rf /Library/Receipts/mysql*
sudo rm -rf /Library/Receipts/MySQL*
sudo rm -rf /private/var/db/receipts/*mysql*
sudo rm /Library/LaunchDaemons/com.oracle.oss.mysql.mysqld.plist

--How to delete mysql entered by brew

$ brew uninstall mysql
sudo rm -rf /usr/local/Cellar/mysql*
sudo rm -rf /usr/local/bin/mysql*
sudo rm -rf /usr/local/var/mysql*
sudo rm -rf /usr/local/etc/my.cnf
sudo rm -rf /usr/local/share/mysql*
sudo rm -rf /usr/local/opt/mysql*
sudo rm -rf /etc/my.cnf

If you run both of the above, all mysql should disappear.

install mysql with brew

This time I will use brew to install mysql. Currently, if you do brew install mysql, 8 series of mysql will be installed, so install 5.7 safely.

brew install [email protected]

Put the following line in the configuration file of the shell you are using to pass the path. (For bash ~/.bash_profile)

export PATH="/usr/local/opt/[email protected]/bin:$PATH"

• If there is a mysql PATH that was set in the past, delete it.

mysql.server start

Starting MySQL
 SUCCESS!

If so, the installation of mysql is successful.

Run a Rails project that was launched in the past

The following are the points of interest when running a rails project.

If it is a project that executed bundle install in the past, I think that the gem is installed according to the version of mysql that was installed at that time, so when I execute rails db: create, the following error appears and mysql surroundings I'm angry! I think you will see the error.

> rails db:create
rails aborted!
LoadError: dlopen

So uninstall the gem with the following command.

bundle exec gem uninstall mysql2

do it

bundle install 

Let's re-insert the mysql2 gem. If you get an error here

bundle config --local build.mysql2 "--with-ldflags=-L/usr/local/opt/openssl/lib"

Try running the above command before bundle install.

reference: https://qiita.com/akiko-pusu/items/aef52b723da2cb5dc596