select version();

CREATE TABLE test ( id INT GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY, t_field TEXT );

INSERT INTO test (t_field) VALUES ('bar$foo$john$doe$xxx'); -- OP's own data

INSERT INTO test (t_field) SELECT LEFT(MD5(RANDOM()::TEXT), FLOOR(RANDOM() * (5 - 3 + 1) + 3)::INT) || '$' || LEFT(MD5(RANDOM()::TEXT), FLOOR(RANDOM() * (5 - 3 + 1) + 3)::INT) || '$' || LEFT(MD5(RANDOM()::TEXT), FLOOR(RANDOM() * (5 - 3 + 1) + 3)::INT) || '$' || LEFT(MD5(RANDOM()::TEXT), FLOOR(RANDOM() * (5 - 3 + 1) + 3)::INT) || '$' || LEFT(MD5(RANDOM()::TEXT), FLOOR(RANDOM() * (5 - 3 + 1) + 3)::INT) FROM GENERATE_SERIES(1, 299999); --<<== Vary here -- -- Vary the GENERATE_SERIES(1, 299999) number if the fiddle run fails! -- -- 299999 (+ 1 - OP) = 300,000 = large enough number to get reliable, consistent results -- and small enough so that the fiddle run doesn't fail too often. --

ANALYZE test;

-- -- --

-- -- 2: - REGEXP_REPLACE() with REVERSE() -- SELECT t_field, REVERSE(REGEXP_REPLACE(REVERSE(t_field), '\$', '-')) AS result FROM test LIMIT 2;

EXPLAIN (ANALYZE, TIMING OFF) SELECT REVERSE(REGEXP_REPLACE(REVERSE(t_field), '\$', '-')) AS result FROM test;