Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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5.5, 10.0, 10.1
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None
Description
The patch for MDEV-6105 made this script
SET NAMES utf8;
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DROP TABLE IF EXISTS t1;
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CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET utf8, KEY(a)) ENGINE=MyISAM;
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INSERT INTO t1 VALUES ('a'),('b'),('c'),('d'),('e');
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EXPLAIN SELECT * FROM t1 WHERE a='��';
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correct;y return "Impossible WHERE":
+------+-------------+-------+------+---------------+------+---------+------+------+-----------------------------------------------------+
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| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
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+------+-------------+-------+------+---------------+------+---------+------+------+-----------------------------------------------------+
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| 1 | SIMPLE | NULL | NULL | NULL | NULL | NULL | NULL | NULL | Impossible WHERE noticed after reading const tables |
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+------+-------------+-------+------+---------------+------+---------+------+------+-----------------------------------------------------+
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However, if I use <=> instead of =, it still switches to full table scan.
It should be fixed to return "Impossible WHERE" for <=>.
Attachments
Issue Links
- relates to
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- Closed
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