Details
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Bug
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Status: Closed (View Workflow)
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Critical
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Resolution: Fixed
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10.2(EOL)
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None
Description
I run this script:
DROP TABLE IF EXISTS t1; |
CREATE TABLE t1 (a BIGINT NOT NULL DEFAULT (IF(false,UNIX_TIMESTAMP(),10))); |
INSERT INTO t1 VALUES (10000); |
SELECT
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a,
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DEFAULT(a), |
CASE WHEN a THEN DEFAULT(a) END AS c, |
CASE WHEN a THEN DEFAULT(a) END = 10 AS ce |
FROM t1; |
It returns the following correct result:
+-------+------------+------+------+
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| a | DEFAULT(a) | c | ce |
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+-------+------------+------+------+
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| 10000 | 10 | 10 | 1 |
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+-------+------------+------+------+
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Looks good so far. The value of the CASE expression (result column c) is correctly evaluates to 10, and the comparison expression (result column ce) correctly evaluates to true.
Now I put the comparison expression into the WHERE clause:
SELECT a FROM t1 WHERE CASE WHEN a THEN DEFAULT(a) END=10; |
Empty set (0.001 sec)
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Looks wrong.
Now I put a breakpoint in Field_longlong::val_int() and rerun the last SQL query with the WHERE condition.
val_int() is called two times:
- I skip the first call which is evaluation of WHEN a
- I print the following values during the second call, which is evaluation of THEN DEFAULT(a):
(gdb) print ptr
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$6 = (uchar *) 0x62b000001a99 "\245\245\245\245\245\245\245\245", '\217' <repeats 15 times>
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(gdb) fin
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Run till exit from #0 Field_longlong::val_int (this=0x62b0000019c8)
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at /home/bar/maria-git/server.10.2.asan/sql/field.cc:4514
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Item_field::val_int_result (this=0x62b000000d88)
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at /home/bar/maria-git/server.10.2.asan/sql/item.cc:2898
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2898 return result_field->val_int();
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Value returned is $7 = -6510615555426900571
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Notice:
- Field_longlong::ptr points to a non-initialized buffer
- val_int() returns a non-relevant value instead of 10
Attachments
Issue Links
- blocks
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- Closed
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- relates to
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- Closed
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