The current integrated search function will compare your keyword to the entire database stored on your iPad as well as the streaming service and radio. This function request a remarkable number of memory to run especially when you have a large music library.
The iPad 2nd generation and iPad mini 1st generation, due to the memory size and processor speed, is not recommended.
The iPad mini 1st generation which only have 512MB system memory may not capable to use the search function when the music library size exceed 20,000 tracks.
Though AURALiC software team is working on improvement, we still recommend you to replace your iPad with latest one to get a much better experience.