--echo #
--echo # Test cases for the secondary_engine_cost_threshold variable.
--echo #

--disable_query_log
--eval INSTALL PLUGIN mock SONAME '$MOCK_PLUGIN'
--enable_query_log

# Remember the original threshold and restore it at the end of the test.
SELECT @@secondary_engine_cost_threshold,
       @@global.secondary_engine_cost_threshold;
SET @saved_threshold = @@secondary_engine_cost_threshold;

# Negative threshold values give a warning and are adjusted to 0.
SET @@secondary_engine_cost_threshold = -100;
SELECT @@secondary_engine_cost_threshold;

CREATE TABLE t1(x INT, y INT);
INSERT INTO t1 VALUES (1, 2), (2, 3), (3, 4);

# A costly Cartesian product to help create plans with high cost.
CREATE VIEW v1 AS
SELECT t1.x x1, t2.x x2, t3.x x3, t4.x x4, t5.x x5, t6.x x6, t7.x x7,
       t8.x x8, t9.x x9, t10.x x10, t11.x x11, t12.x x12, t13.x x13
FROM t1, t1 t2, t1 t3, t1 t4, t1 t5, t1 t6, t1 t7, t1 t8, t1 t9,
     t1 t10, t1 t11, t1 t12, t1 t13;

ANALYZE TABLE t1;

# Some queries with different costs.
let $q1 = SELECT * FROM t1;
let $q2 = SELECT (SELECT y FROM t1 WHERE x = 1);
let $q3 = SELECT * FROM v1;
let $q4 = SELECT * FROM t1 WHERE x = (SELECT COUNT(*) FROM v1);
let $q5 = SELECT * FROM t1 tt WHERE x = (SELECT SUM(x) FROM t1);
let $q6 = SELECT * FROM t1 tt
            WHERE x IN (SELECT SUM(x) FROM t1 WHERE x = (SELECT tt.y));

--eval EXPLAIN $q1
SHOW STATUS LIKE 'Last_query_cost';
--eval EXPLAIN $q2
SHOW STATUS LIKE 'Last_query_cost';
--eval EXPLAIN $q3
SHOW STATUS LIKE 'Last_query_cost';
--eval EXPLAIN $q4
SHOW STATUS LIKE 'Last_query_cost';
--eval EXPLAIN $q5
SHOW STATUS LIKE 'Last_query_cost';
--eval EXPLAIN $q6
SHOW STATUS LIKE 'Last_query_cost';

ALTER TABLE t1 SECONDARY_ENGINE MOCK;
ALTER TABLE t1 SECONDARY_LOAD;
ANALYZE TABLE t1;

# The threshold is 0. Queries with non-zero cost are offloaded.
SET @@secondary_engine_cost_threshold = 0;
SELECT @@secondary_engine_cost_threshold,
       @@global.secondary_engine_cost_threshold;

FLUSH STATUS;
--eval EXPLAIN $q1
--eval $q1
--eval EXPLAIN $q2
--eval $q2
--eval EXPLAIN $q3
--eval $q3
--eval EXPLAIN $q4
--eval $q4
--eval EXPLAIN $q5
--eval $q5
--eval EXPLAIN $q6
--eval $q6
SHOW STATUS LIKE 'Secondary_engine_execution_count';

# Increase the threshold. Only the two most expensive queries are offloaded.
SET @@secondary_engine_cost_threshold = 100;
SELECT @@secondary_engine_cost_threshold,
       @@global.secondary_engine_cost_threshold;

FLUSH STATUS;
--eval EXPLAIN $q1
--eval $q1
--eval EXPLAIN $q2
--eval $q2
--eval EXPLAIN $q3
--eval $q3
--eval EXPLAIN $q4
--eval $q4
--eval EXPLAIN $q5
--eval $q5
--eval EXPLAIN $q6
--eval $q6
SHOW STATUS LIKE 'Secondary_engine_execution_count';

# Increase the threshold even more. All the queries should be executed
# in the primary storage engine.
SET @@secondary_engine_cost_threshold = 1000000;
SELECT @@secondary_engine_cost_threshold,
       @@global.secondary_engine_cost_threshold;
--eval EXPLAIN $q1
--eval EXPLAIN $q2
--eval EXPLAIN $q3
--eval EXPLAIN $q4
--eval EXPLAIN $q5
--eval EXPLAIN $q6

# Set the threshold in a hint.
EXPLAIN SELECT /*+ SET_VAR(secondary_engine_cost_threshold = 0) */ * FROM t1;
EXPLAIN SELECT /*+ SET_VAR(secondary_engine_cost_threshold = 100) */ * FROM t1;

# The use_secondary_engine variable overrides the threshold.
EXPLAIN
SELECT /*+ SET_VAR(secondary_engine_cost_threshold = 1000000)
           SET_VAR(use_secondary_engine = FORCED) */
  * FROM t1;
EXPLAIN
SELECT /*+ SET_VAR(secondary_engine_cost_threshold = 0)
           SET_VAR(use_secondary_engine = OFF) */
  * FROM t1;

# The threshold is evaluated on each execution.
FLUSH STATUS;
--eval PREPARE ps FROM '$q1'
SET @@secondary_engine_cost_threshold = 0;
EXECUTE ps;
SHOW STATUS LIKE 'Secondary_engine_execution_count';
SET @@secondary_engine_cost_threshold = 100;
EXECUTE ps;
SHOW STATUS LIKE 'Secondary_engine_execution_count';
SET @@secondary_engine_cost_threshold = 0;
EXECUTE ps;
SHOW STATUS LIKE 'Secondary_engine_execution_count';
SET @@secondary_engine_cost_threshold = 100;
EXECUTE ps;
SHOW STATUS LIKE 'Secondary_engine_execution_count';
DROP PREPARE ps;

DROP TABLE t1;
DROP VIEW v1;

# Restore the original value of the threshold.
SET @@secondary_engine_cost_threshold = @saved_threshold;
SELECT @@secondary_engine_cost_threshold,
       @@global.secondary_engine_cost_threshold;

UNINSTALL PLUGIN mock;