Details
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Bug
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Status: Open (View Workflow)
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Minor
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Resolution: Unresolved
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5.5(EOL), 10.0(EOL), 10.1(EOL)
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None
Description
CREATE OR REPLACE ALGORITHM = MERGE VIEW v AS |
SELECT 1 a, SLEEP(3) b, SLEEP(3) c FROM DUAL; |
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EXPLAIN EXTENDED
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SELECT a FROM v; |
EXPLAIN EXTENDED shows us what we want to see... but it's a lie 
If you execute the SELECT, it will sleep for 6 seconds, because columns b and c are evaluated.
Note that the bug will NOT happen in this case:
\W
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CREATE OR REPLACE TABLE t (a INT) ENGINE = InnoDB; |
INSERT INTO t VALUES (1); |
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CREATE OR REPLACE ALGORITHM = MERGE VIEW v AS |
SELECT a, SLEEP(3) b, SLEEP(3) c FROM t; |
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EXPLAIN EXTENDED
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SELECT a FROM v; |