This stored procedure only runs when there is something that's trying to modify a document page. It is probably being run as part of page thumbnail generation. Please check the rows of the dboptions table to see if there's a row where optionname = 'BackgroundThumbnailGenerator'. If so, you can disable thumbnail generation by setting the optionvalue column to '0' for that row and restarting LFS.

There is a way to schedule when this runs but it's a bit complex to explain, so first please verify if that row is present in the dboptions table and if your client is willing to simply disable it. If that row is not present then further investigation will be required.