pub const STRING_PREFIX_CHARS: usize = 512;Expand description
How many leading characters of a string value its prefix B-tree covers.
A B-tree entry must fit in a third of a page (2704 bytes), and a long
narrative such as a ValueSet.description does not. Indexing only the
first characters keeps every value indexable: at most four UTF-8 bytes a
character, this many fit with room for the scope columns. A prefix term is
never this long, so a search loses nothing; the full value is still stored
and the trigram index still covers all of it.