I have encountered this issue about a week ago, when i'm exporting my database through phpMyAdmin tool, the export works very well and the output file is up to 10 MB in size. The main issue comes when i would like to import it back using phpMyAdmin, but guess what happened, a timeout occured.
I will kindly break it down for you, there are 2 limitations surrounding phpMyAdmin from importing a very large MySQL database:
1. A time out is divided into a server timeout and browser timeout. This basically means when a script is being executed for too long that it has eventually passed the time limit either on the server and/or browser, the script will cease to run. Simply put, the larger your file is, the longer it takes to be executed, the bigger chance it fails.
You could actually bypass the browser timeout by modifying the about:config setting if you are on Firefox, unfortunately for server timeout, if you are on shared hosting like me, you are unlikely to get access to modify the server config.
2. File size limit on certain web hosting companies. Normally, i would say a 10 MB filesize limit is being implemented by most web hosting companies, if your MySQL filesize is more than that, then you're out of luck. Fortunately, my hosting company (BlueHost) is generous by allowing me to upload up to 50 MB filesize.
