# name: test/optimizer/limit_pushdown.test
# description: Test Limit Pushdown optimization
# group: [optimizer]

statement ok
CREATE TABLE integers(i INTEGER, j INTEGER)

statement ok
PRAGMA explain_output = OPTIMIZED_ONLY;

statement ok
INSERT INTO integers VALUES (1,1), (2,2), (3, 3), (4,4)

# project + limit becomes limit + project
query II
EXPLAIN SELECT i FROM integers LIMIT 4
----
logical_opt	<REGEX>:.*PROJECTION.*LIMIT.*

# verify result for project + limit to limit + project
query I
SELECT i FROM integers LIMIT 4
----
1
2
3
4

# recursive limit pushdown
query II
EXPLAIN SELECT i FROM (SELECT i, i+1 FROM integers) LIMIT 4
----
logical_opt	<REGEX>:.*PROJECTION.*PROJECTION.*LIMIT.*

# verify result for recursive limit pushdown and offset
query I
SELECT i FROM (SELECT i, i+1 FROM integers) LIMIT 4 OFFSET 2
----
3
4

# only offset: no pushdown
query II
EXPLAIN SELECT i FROM integers OFFSET 4
----
logical_opt	<REGEX>:.*LIMIT.*PROJECTION.*

# limit and offset
query II
EXPLAIN SELECT i FROM integers LIMIT 4 OFFSET 2
----
logical_opt	<REGEX>:.*PROJECTION.*LIMIT.*

# verify result for limit and offset
query I
SELECT i FROM integers LIMIT 4 OFFSET 2
----
3
4

# limit value > 8192: no pushdown
query II
EXPLAIN SELECT i FROM integers LIMIT 8192
----
logical_opt	<REGEX>:.*LIMIT.*PROJECTION.*