query using IntersectScan vs UnionScan

CREATE INDEX ix1 ON default (c1, c2, cdate) WHERE type = "doc";

CREATE INDEX ix2 ON default (c1, c2, c3, ldate DESC) WHERE type = "doc";

EXPLAIN SELECT *

FROM default

WHERE type = "doc"

      AND c1 = 10

      AND ( c3 = "abc" OR c2 = "xyz" )

ORDER BY ldate DESC

LIMIT 150;

CREATE INDEX ix3 ON default(c1, ldate DESC, c2, c3 ) WHERE type = "doc";