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 ivfflat (val bit_hamming_ops) WITH (lists = 1); 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; -- varbit CREATE TABLE t (val varbit(3)); CREATE INDEX ON t USING ivfflat (val bit_hamming_ops) WITH (lists = 1); CREATE INDEX ON t USING ivfflat ((val::bit(3)) bit_hamming_ops) WITH (lists = 1); CREATE INDEX ON t USING ivfflat ((val::bit(64001)) bit_hamming_ops) WITH (lists = 1); CREATE INDEX ON t USING ivfflat ((val::bit(2)) bit_hamming_ops) WITH (lists = 5); DROP TABLE t; -- dimensions CREATE TABLE t (val bit(64000)); CREATE INDEX ON t USING ivfflat (val bit_hamming_ops); DROP TABLE t; CREATE TABLE t (val bit(64001)); CREATE INDEX ON t USING ivfflat (val bit_hamming_ops); DROP TABLE t; -- memory SET maintenance_work_mem = '1MB'; CREATE TABLE t (val bit(64000)); CREATE INDEX ON t USING ivfflat (val bit_hamming_ops); DROP TABLE t; RESET maintenance_work_mem; SET maintenance_work_mem = '29MB'; CREATE TABLE t (val bit(64000)); INSERT INTO t (val) VALUES (B'0'::bit(64000)); CREATE INDEX ON t USING ivfflat (val bit_hamming_ops); DROP TABLE t; RESET maintenance_work_mem;