binary_part is allowed in matchspecs, so in principle you could use that for the starts_with search. That won’t help with contains, though…

While it’s faster than many other approaches :ets.select is still going to be time-consuming if the table is large; it’s like always doing a sequential-scan in a full-size DBMS.

The solution to that for ETS is similarly parallel: create additional tables that speed up important queries. For instance, you can make “starts with” queries efficient if you maintain a second :bag table like:

{"F", 1}
{"Fr", 1}
{"Fre", 1}
{"Fred", 1}
{"F", 2}
{"Fr", 2}
{"Fre", 2}
{"Fred", 2}
{"Frede", 2}
{"Freder", 2}
{"Frederi", 2}
{"Frederic", 2}
{"Frederich", 2}
{"B", 3}
{"Ba", 3}
{"Bar", 3}
{"Barn", 3}
{"Barne", 3}
{"Barney", 3}

Like any index, this trades memory usage for retrieval speed.

Indexing for “contains” is harder but there are well-documented techniques like trigram indexing that can help.