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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5.5.51, 10.1.16, 10.1.17, 10.0.27, 5.5(EOL), 10.0(EOL), 10.1(EOL)
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None
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We reproduce crash on multiple server/configs with:
10.0.27 on debian wheezy, debian jessie
10.1.16, 10.1.17 on debian jessie
Query work fine on 10.0.26
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10.1.18
Description
You can use this query to reproduce crash:
drop table if exists dummy; |
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create table dummy ( |
field1 int |
) engine=innodb default charset=utf8; |
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insert into dummy values (1); |
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select round((select 1 from dummy limit 1)) |
from dummy |
group by round((select 1 from dummy limit 1)); |
Regards,
Vincent
Attachments
Activity
Note: the above example from gschulman actually doesn't parse due to the way how FROM dual is handled in MySQL. If one replaces dual with some other table, it works.
Thanks psergey for working on this.
Not sure if I understand your comment about my example, but I can reproduce the bug both ways, using dual or using a table. Let me share it from my console:
Welcome to the MariaDB monitor. Commands end with ; or \g.
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Your MariaDB connection id is 39
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Server version: 10.1.17-MariaDB-1~precise mariadb.org binary distribution
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Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.
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Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
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MariaDB [(none)]> use test
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Reading table information for completion of table and column names
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You can turn off this feature to get a quicker startup with -A
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Database changed
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MariaDB [test]> SELECT concat((SELECT "a" from d),"b")
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-> FROM dual
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-> GROUP BY concat((SELECT "a" from d),"b");
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ERROR 2013 (HY000): Lost connection to MySQL server during query
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MariaDB [test]>
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Here the server crashed and restarted.
MariaDB [test]> create table a (i integer);
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Query OK, 0 rows affected (0.01 sec)
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MariaDB [test]>
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MariaDB [test]> SELECT concat((SELECT "a" from d),"b")
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-> FROM a
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-> GROUP BY concat((SELECT "a" from d),"b");
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ERROR 2006 (HY000): MySQL server has gone away
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No connection. Trying to reconnect...
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Connection id: 2
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Current database: test
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ERROR 2013 (HY000): Lost connection to MySQL server during query
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MariaDB [test]>
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gschulman, thanks for the note.
The patch was made against MariaDB-10.0. I can confirm that our example with FROM a works on the patched 10.0.
However, 10.0 gives a parse error for the FROM dual variant. The patch for this issue hasn't been merged into MariaDB-10.1 yet, but I think we have all reasons to believe that the FROM dual variant will work too when the patch is merged into 10.1.
Oh, ok, now it's clear what you meant, psergey.
BTW, even if the fix seems to be already pushed, let me add:
1 - it can be reproduced by just running the EXPLAIN for those queries, clearly meaning that the problem was in the planner.
2 - replacing GROUP BY by ORDER BY in those queries also triggers the problem.
Thanks again.
Ok to push. Sorry for the delay.