I am experiencing a very slow query when Toolset is activated, along with WP Offload Media. The slow query only happens when Toolset is activated.
I have installed Query monitor and according to that plugin there is a conflict with post meta with a meta key of "_wp_attached_file" and a value that has a .tmp file name. WP Offload Media is responding to the "wp_unique_filename" filter call to ensure that it has not offloaded something that could have a name clash with the newly proposed file name.
I found that this file: types\vendor\otgs\installer\includes\class-installer-dependencies.php contains code that is part of the problem with the slow query. When I comment out the code in the attached screenshot, it is no longer included in the slow queries in query monitor and the admin is much faster. Can you explain what this piece of code does and why it is trying to delete a file that does not exist?
I just checked with the internal ticket reported and there is no news yet to share with you.
But I had a talk with Dev and the update is that they will try to propose fix as soon as possible but there is no ETA on it. I'll get in touch with you as soon as I get any updates on it.