high load

I’ve used this plugin for a very long time. It used to do its job in just a few seconds and was so efficient.

But over the past couple weeks (I didn’t notice exactly when), something’s changed: it usually spikes the load on my server (VPS) and my site is inaccessible. If I am able to run it successfully (rarely) it takes a long time to complete, two or three minutes).

Any suggestions? I’ve tried similar plugins but this is by far my favorite, and I hope to be able to use it again.