That's interesting, and doesn't surprise me. When I wrote an n-gram full-text search for email 20 years ago, I used 4-grams to get the required selectivity. I i

That's interesting, and doesn't surprise me. When I wrote an n-gram full-text search for email 20 years ago, I used 4-grams to get the required selectivity. I imagine code could be worse because of more restricted syntax and alphabet. However, this doesn't bear directly on the question of trigrams-over-UTF8-bytes vs trigrams-over-Unicode-chars.