I believe I made a mistake by creating about 15,000 entries in a Structure section. It has caused a lot of problems and so I decided to start again with a Channel section instead. I tried deleting the old section to remove the entries but it crashes mysql. Does anyone know a way to remove entries and their content in the database?
I think I did this successfully with help from another answer on here. I removed the data from the craft_elements table by using the fieldLayoutId column to identify the entry type I wanted to remove. Seems it removed the data from the other tables as well.