Today I backed up my site using the Export function in PHPMyAdmin. The final uncompressed file was 85 Mb. One reason for the backup was to load the data back into the local version running on my laptop. Needless to say, loading a 85 Mb file took quite a while.
While this was happening, I discovered that most of the file size came from the PageView table. Since this is effectively a set of log files, the size is not surprising but it made backing up and restoring a real pain. I didn't need the data and excluding that data gave me a 17 Mb file.
I guess this is just a warning for others - don't include the PageView table in your backups unless you really need to back up that data. Alternatively, back it up separately, so you can restore without it.
And finally, if you have access to the PHPMyAdmin folder on the machine you are restoring to, here is a way of getting around the 2Mb limit on file imports: