SET enable_seqscan = off; -- hamming CREATE TABLE t (val bit(3)); INSERT INTO t (val) VALUES (B'000'), (B'100'), (B'111'), (NULL); CREATE INDEX ON t USING hnsw (val bit_hamming_ops); INSERT INTO t (val) VALUES (B'110'); SELECT * FROM t ORDER BY val <~> B'111'; SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <~> (SELECT NULL::bit)) t2; DROP TABLE t; -- jaccard CREATE TABLE t (val bit(4)); INSERT INTO t (val) VALUES (B'0000'), (B'1100'), (B'1111'), (NULL); CREATE INDEX ON t USING hnsw (val bit_jaccard_ops); INSERT INTO t (val) VALUES (B'1110'); SELECT * FROM t ORDER BY val <%> B'1111'; SELECT COUNT(*) FROM (SELECT * FROM t ORDER BY val <%> (SELECT NULL::bit)) t2; DROP TABLE t; -- varbit CREATE TABLE t (val varbit(3)); CREATE INDEX ON t USING hnsw (val bit_hamming_ops); CREATE INDEX ON t USING hnsw ((val::bit(3)) bit_hamming_ops); CREATE INDEX ON t USING hnsw ((val::bit(64001)) bit_hamming_ops); DROP TABLE t;