Craft 3: Search in 15000 entries
Craft can handle such an amount of elements really well but you could get in trouble when you are going to import them all at once without changing your web server config or using certain importers since it will extend the defaults max_execution_time. So you'll have to import them step by step or via queue (or via import plugin).

I created a job center with about 60.000 elements currently and everything works smooth