I have no idea what a "numeric bigint" is. However, the native integer type in SQLite is an 8-byte signed integer. A 128-byte string is 16 times longer than an 8 byte signed integer. Therefore, one would assume that "searching" 128-byte "things" will take 16 times longer than searching 8 byte "things" simply because the 128-byte "thing" is 16 times bigger than the 8-byte "thing". That one would even need to ask such a question is surprising. As to the performance of an index that would depend on the depth and breadth of the index. However, given an equivalent page size, you can fit 16 times more 8-byte keys on a page than you can fit 128-byte keys -- so one would expect the search time taken with 128-byte keys to increase at a rate 16 times faster than it does with 8-byte keys simply because the index will have higher breadth and depth by a factor of 16, and will require 16 times the I/O. I should think that this would also be obvious. If you want to know the particulars for your specific data and implementation, you will have to actually give it a try.