Earlier this year, I wrote a long post about log shipping. One of the key points I mentioned was how slow restoring can be for a read only log shipped database. If going and reading the whole thing is too much effort for you now, I’ll save you the effort (you child of the internet you) and tell you it’s because the database needs to be kept transactionally consistent in between restores when making it available for read-only. It creates a .tuf file (transaction undo file) to keep the progress of all the pages that have uncommitted transactions saved to them. The checking, creation, applying and re-applying of this can take some time where there is a significant amount of uncommitted transactions within a log backup.