opt_costmodel_restart.test

#
# Test of the cost constants when restarting the server
#

# Can not run with embedded server since it requires server restarts
-- source include/not_embedded.inc

# To get stable cost estimates, the test should only be run with 
# 16K InnoDB page size.
--source include/have_innodb_16k.inc

#
# Test that changes to cost constants are used after restarting server
#

# Verify that the content of the two cost constants tables are as expected
SELECT cost_name,cost_value FROM mysql.server_cost;
SELECT engine_name,cost_name,cost_value FROM mysql.engine_cost;

#
# Create a test database that will be used for running queries
#
CREATE TABLE t0 (
  i1 INTEGER
);

INSERT INTO t0 VALUE (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

# Create a table with 100 records each having size approximately 1000 bytes
CREATE TABLE t1_innodb (
  pk INTEGER PRIMARY KEY,
  i1 INTEGER NOT NULL,
  c1 CHAR(250),
  c2 CHAR(250),
  c3 CHAR(250),
  c4 CHAR(250),
  INDEX i1_key (i1)
) ENGINE=InnoDB;

INSERT INTO t1_innodb
SELECT a0.i1 + 10 * a1.i1, a0.i1, 'abc', 'def', 'ghi', 'jkl'
FROM t0 AS a0, t0 AS a1;

# Create the same table in MyISAM
CREATE TABLE t1_myisam (
  pk INTEGER PRIMARY KEY,
  i1 INTEGER NOT NULL,
  c1 CHAR(250),
  c2 CHAR(250),
  c3 CHAR(250),
  c4 CHAR(250),
  INDEX i1_key (i1)
) ENGINE=MyISAM;

INSERT INTO t1_myisam
SELECT a0.i1 + 10 * a1.i1, a0.i1, 'abc', 'def', 'ghi', 'jkl'
FROM t0 AS a0, t0 AS a1;

ANALYZE TABLE t1_innodb, t1_myisam;

# Run two queries to see cost estimates when run with default cost constants
let query_innodb= SELECT * FROM t1_innodb;
let query_myisam= SELECT * FROM t1_myisam;

--echo "Explain with cost estimate against InnoDB"
eval EXPLAIN FORMAT=JSON $query_innodb;
--echo "Explain with cost estimate against MyISAM"
eval EXPLAIN FORMAT=JSON $query_myisam;

#
# Update one cost constant in each of the two cost constant tables.
# The new value is double of the default value.
#
UPDATE mysql.server_cost 
SET cost_value=0.4
WHERE cost_name="row_evaluate_cost";

UPDATE mysql.engine_cost 
SET cost_value=2.0
WHERE cost_name="memory_block_read_cost";

--echo "Restarting MySQL server"
--source include/restart_mysqld.inc
--echo "MySQL restarted"

SELECT cost_name,cost_value FROM mysql.server_cost;
SELECT engine_name, cost_name,cost_value FROM mysql.engine_cost;

#
# Run the two queries an validate that the cost estimate has doubled
#
--echo "Explain with cost estimate against InnoDB"
eval EXPLAIN FORMAT=JSON $query_innodb;
--echo "Explain with cost estimate against MyISAM"
eval EXPLAIN FORMAT=JSON $query_myisam;

# Reset the cost constants
UPDATE mysql.server_cost
SET cost_value=DEFAULT;
UPDATE mysql.engine_cost
SET cost_value=DEFAULT;

#
# Test that adding an engine specific cost constant does not influence
# other engines.
#
INSERT INTO mysql.engine_cost VALUES
  ("InnoDB", 0, "memory_block_read_cost", 4.0, CURRENT_TIMESTAMP, DEFAULT);

--echo "Restarting MySQL server"
--source include/restart_mysqld.inc
--echo "MySQL restarted"

#
# Run the two queries and validate that the query against MyISAM has
# the original cost estimates while the read cost for InnoDb should
# be four times the original
#
--echo "Explain with cost estimate against InnoDB"
eval EXPLAIN FORMAT=JSON $query_innodb;
--echo "Explain with cost estimate against MyISAM"
eval EXPLAIN FORMAT=JSON $query_myisam;

# Delete the added entry for InnoDB
DELETE FROM mysql.engine_cost
WHERE engine_name NOT LIKE "default";

--echo "Restarting MySQL server"
--source include/restart_mysqld.inc

DROP TABLE t0, t1_innodb, t1_myisam;