I have just released version 1.00, which contains enhancements to the “where-used” reporting that requires a lot of SQL processing.
There are four where-used reporting categories; Featured In, Inserted In, Gallery In and MLA Gallery In. Any of the four categories can be disabled if performance is an issue and the information is not immediately useful.
The Gallery In and MLA Gallery In categories require the most SQL processing. By default, they are now run once and cached for ten minutes before updating again. You can set these categories to “Dynamic” if updating on each page load is required. The cache is also flushed when posts or pages are updated.
I believe these features address the issue you’ve raised. If there are other performance concerns, I’d love more information so I can work on anything else that’s causing trouble.
Thanks again for your interest in the plugin.