What size is the db (post count)?
If there are like 10k post, then some tweaking might be needed. The 100% peak usage is not an issue, it can go up to 100% in search queries for a very short time. The issue is if it stays up on 100% for a long time, then the server might or might not crash.
Do you have a swap file enabled? MySQL likes to use a lot of memory, and by lot I mean a hell of a LOT. When I moved this site I forgot to turn on the swap file, and after just installing a plain new empty WordPress it crashed after the 3rd refresh, and this server uses 1G memory.
If the swap file is okay, then there are lots of other options to tweak:
If you have a bigger database, like 10k posts you should consider turning off the content relevance as there is a very high chance that title relevance will match other titles. You can do that on the “Relevance Options” panel by turning off the “Look in content?” option.
Plus another and possibly the most effective tweak is to reduce the keyword count, it exponentially affects the speed of the query. So again on the “Relevance Options” try to reduce the “Keywords maximum count” from 10 to 3. Depending on the database size this should improve the performance extremely.
Or maybe your server doesn't like the boolean mode search. What if you turn off the fulltext search. On the “Advanced Options” panel:
- Turn OFF the “Use fulltext lookup if available?”
- Turn ON the “Enable cache?”
Altough fulltext search should be more effective in terms of performance, in some cases I found it's exactly the other way around. There is no other way to know, but testing.
You can try experimenting with these options, these control the most of the resources.
Let me know which of these helped, I'm all in for feedback. I must close the office now, it's getting too late here. Will get back to you tomorrow morning. Hopefully these suggestions will help.Best,
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