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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6.1.1
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None
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2021-10
Description
I create a MyISAM table with some string columns with the latin1_bin collation, insert 122881 records and run a query with a WHERE condition which matches all those records:
DROP TABLE IF EXISTS t1; |
CREATE TABLE t1 |
(
|
l_returnflag char(1) CHARACTER SET latin1 COLLATE latin1_bin, |
l_shipinstruct char(25) CHARACTER SET latin1 COLLATE latin1_bin, |
l_comment varchar(44) CHARACTER SET latin1 COLLATE latin1_bin |
) ENGINE=MyISAM;
|
|
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DELIMITER $$
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FOR i IN 1..122881 |
DO
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INSERT INTO t1 VALUES ('a', 'aaaa','AAAA'); |
END FOR; |
$$
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DELIMITER ;
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SELECT count(*) FROM t1 WHERE l_comment < l_shipinstruct; |
It returns all records as expected:
+----------+
|
| count(*) |
|
+----------+
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| 122881 |
|
+----------+
|
Now I make a ColumnStore table with the same structure and data and run the same SELECT query:
DROP TABLE IF EXISTS t2; |
CREATE TABLE t2 LIKE t1; |
ALTER TABLE t2 ENGINE=ColumnStore; |
INSERT INTO t2 SELECT * FROM t1; |
SELECT count(*) FROM t2 WHERE l_comment < l_shipinstruct; |
+----------+
|
| count(*) |
|
+----------+
|
| 1 |
|
+----------+
|
Notice, it returns a wrong result.
Moreover, if I repeat the last query multiple times, it can also return a result like this:
+----------+
|
| count(*) |
|
+----------+
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| 122880 |
|
+----------+
|
But it never returns the expected result 122881.
The problem happens because this method:
SCommand StrFilterCmd::duplicate()
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{
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SCommand ret;
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StrFilterCmd* filterCmd;
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|
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ret.reset(new StrFilterCmd()); |
filterCmd = (StrFilterCmd*) ret.get();
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filterCmd->fBOP = fBOP;
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filterCmd->fCompare = fCompare;
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filterCmd->fCharLength = fCharLength;
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|
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return ret; |
}
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misses these two lines:
filterCmd->leftColType = leftColType;
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filterCmd->rightColType = rightColType;
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Note, the same method of the parent class, i.e. FilterCommand::duplicate(), does have these two lines!
StrFilterCmd::duplicate() fully duplicates FilterCommand::duplicate() with the exeption that the mentioned two members are not coppied.
To fix this problem and to avoid similar bugs in the future, the duplicate code should be removed.
StrFilterCmd::duplicate() should just call the inherited FilterCommand::duplicate(), then additionally copy its specific members.
Attachments
Issue Links
- blocks
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MCOL-4791 Fix ColumnCommand fudged data type format to clearly identify CHAR vs VARCHAR
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- Stalled
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