I created the 4.0.5 – available as development version so far.
You should see a very significant decrease of the SQL transactions. On the “player” page with no tag selected, I moved from 100 to less than 20. So the plugin is more “quiet” when no operations are required.
https://downloads.www.ads-software.com/plugin/wp-mediatagger.zip
Then running image search involves heavy SQL computing, although down to the minimum with this version. That’s intrinsic to the plugin function, I cannot change this – unless working on a dump of the media database, which I already tried : in this case the SQL server is much less loaded, but the load is transferred on the PHP. At the end my take is that the SQL server is typically profiled for sustaining this kind of computation.
At least the load is now directly driven by the number of media and tags.
Let me know if you notice any involvment, or any other side effect. I tested in all possible situations, should be fine.
I will then promote it to 4.0.5.