I have a php application on heroku which runs on wordpress , I deployed it on heroku a few months ago and it was working well . Later , I updated the application on my localhost and added some plugins for wordpress and deployed it again , now it shows an error on my website , ( Your PHP installation appears to be missing the MySQL extension which is required by WordPress. ) If I restore the website to the previous commit then it works well again . The plugin I am using for mysql is cleardb ignite . Other than that I have also installed sendgrid . I had a local copy of the online application , which I copied by using some git command . To deploy it again to the server I used these commands ,
>heroku login
(go to local project dir , copy the new plugin in the plugins dir)
>git add .
>git commit -m " new plugin added"
>git push heroku master
After this it shows the error . Here is the link to application , http://hearsid.herokuapp.com/ . Other than the above , I tried heroku restart , heroku restart -a my-app-name and heroku , heroku maintainence:off and on . Nothing is working .
Follow the docs (https://devcenter.heroku.com/articles/php-support#extensions) to enable optional extensions such as ext/mysql, or better, upgrade your WordPress to 3.9, which finally has MySQLi support.