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# Test needs MyISAM storage engine
--source include/force_myisam_default.inc
--source include/have_myisam.inc
--echo #
--echo # Bug#23508576 FILL_INDEXES_FROM_DD() DOES NOT INITIALIZE
--echo # ST_KEY::M_IN_MEMORY_ESTIMATE
--echo #
# Adjust cost constants to be different for reading pages from a memory
# buffer compared to reading from disk.
# Cost for reading pages from memory to 0.5
UPDATE mysql.engine_cost
SET cost_value=0.5
WHERE cost_name="memory_block_read_cost";
# Cost for reading pages from disk to 2.0
UPDATE mysql.engine_cost
SET cost_value=2
WHERE cost_name="io_block_read_cost";
FLUSH OPTIMIZER_COSTS;
# Validate that the cost constants have been updated
SELECT engine_name, device_type, cost_name, cost_value
FROM mysql.engine_cost
WHERE cost_name="memory_block_read_cost"
OR cost_name="io_block_read_cost";
# Table must be stored in a storage engine that does not provide
# estimates for how much of the index pages that are in a buffer
CREATE TABLE t1 (
i1 INTEGER,
c1 CHAR(200),
INDEX idx (i1)
) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1, "Ullensvang"), (2, "Odda"), (3, "Jondal");
# Create a user connection
connect (con1,localhost,root,,);
--echo # Pass criteria for the query plan:
--echo # 1. Should be executed as an index-only range scan
--echo # 2. Cost estimate: "read_cost" - "eval_cost" should be approximately
--echo # the cost of reading one page from memory, ie. about 0.5.
--skip_if_hypergraph # Depends on the query plan.
EXPLAIN FORMAT=JSON
SELECT i1 FROM t1 WHERE i1 > 1;
disconnect con1;
--source include/wait_until_disconnected.inc
connection default;
DROP TABLE t1;
# Reset cost constants for storage engines to default values
UPDATE mysql.engine_cost
SET cost_value=DEFAULT;
FLUSH OPTIMIZER_COSTS;
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