@horizonofchaos - Thanks for letting the community know about this potential MySQL issue. I (Cais) use HostGator myself and have not seen any issues but I also do not have anywhere near the total images on any of my sites using NextGEN Gallery.
We would greatly appreciate it if you could send us a bug report about this issue on your site. Please use the form on this page: http://www.nextgen-gallery.com/report-bug/
Feel free to add MySQL as part of the "Issue Title", too.
We have seen reports of other MySQL issues that may be related. If any other readers are having similar issues please feel free to submit your own Bug Report as well.
Thanks!
- Cais.
PS: This is being addressed as a high priority, but in the meantime you may see some relief with the following:
Go to Gallery > Settings > Miscellaneous > Clear Image Cache.