Details
Description
The problem is repeatable with at least MyISAM and InnoDB.
SET @@optimizer_trace='enabled=on'; |
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CREATE OR REPLACE TABLE t1 ( |
a CHAR(2) NOT NULL PRIMARY KEY, |
b VARCHAR(20) NOT NULL, |
KEY (b) |
) ENGINE=InnoDB CHARSET=utf8mb4;
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|
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CREATE OR REPLACE TABLE t2 ( |
a CHAR(2) NOT NULL PRIMARY KEY, |
b VARCHAR(20) NOT NULL, |
KEY (b) |
) ENGINE=InnoDB CHARSET=utf8mb4;
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INSERT INTO t1 VALUES |
('AB','MySQLAB'), |
('JA','Sun Microsystems'), |
('MS','Microsoft'), |
('IB','IBM- Inc.'), |
('GO','Google Inc.'); |
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INSERT IGNORE INTO t2 VALUES |
('AB','Sweden'), |
('JA','USA'), |
('MS','United States of America'), |
('IB','North America'), |
('GO','South America'); |
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UPDATE t1,t2 SET t1.b=UPPER(t1.b) WHERE t1.b LIKE 'Unknown%'; |
ERROR 1406 (22001): Data too long for column 'b' at row 1
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The above error is not expected.
Additionally, in some versions (at least 11.3 and higher), warnings are produced in a simpler script:
SET @@optimizer_trace='enabled=on'; |
|
|
CREATE OR REPLACE TABLE t1 ( |
a CHAR(2) NOT NULL PRIMARY KEY, |
b VARCHAR(20) NOT NULL, |
KEY (b) |
) ENGINE=InnoDB CHARSET=utf8mb4;
|
|
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INSERT INTO t1 VALUES |
('AB','MySQLAB'), |
('JA','Sun Microsystems'), |
('MS','Microsoft'), |
('IB','IBM- Inc.'), |
('GO','Google Inc.'); |
|
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UPDATE t1 SET t1.b=UPPER(t1.b) WHERE t1.b LIKE 'Unknown%'; |
+---------+------+----------------------------------------+
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| Level | Code | Message |
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+---------+------+----------------------------------------+
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| Warning | 1265 | Data truncated for column 'b' at row 1 |
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| Warning | 1265 | Data truncated for column 'b' at row 1 |
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| Warning | 1265 | Data truncated for column 'b' at row 1 |
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| Warning | 1265 | Data truncated for column 'b' at row 1 |
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+---------+------+----------------------------------------+
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These warnings are not expected.
The problem seems to be in the fact that the call for like_range() in Item_func_like::get_mm_leaf() produces more characters than the size of the index.
The patch below fixes the problem, but the real patch should probably fix like_range() not to return more characters than the size of the index.
index 5793b19f695..108b4ac78ae 100644
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--- a/sql/opt_range.cc
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+++ b/sql/opt_range.cc
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@@ -9174,6 +9174,19 @@ Item_func_like::get_mm_leaf(RANGE_OPT_PARAM *param,
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&min_length, &max_length))
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DBUG_RETURN(0); // Can't optimize with LIKE |
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+ min_length= Well_formed_prefix(field->charset(),
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+ (const char *) min_str + offset, min_length, |
+ field->char_length()).length();
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+ max_length= Well_formed_prefix(field->charset(),
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+ (const char *) max_str + offset, max_length, |
+ field->char_length()).length();
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if (offset != maybe_null) // BLOB or VARCHAR |
{
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int2store(min_str + maybe_null, min_length);
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Attachments
Issue Links
- blocks
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MDEV-19123 Change default charset from latin1 to utf8mb4
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- Closed
-