Details
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Type:
Bug
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Status: Closed
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Priority:
Minor
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Resolution: Fixed
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Affects Version/s: 10.0.3
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Fix Version/s: 10.0.4
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Component/s: None
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Labels:
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Environment:Linux/Ubuntu/Precise/LXContainer
Description
Creating a pivot table (Connect SE) and selecting from the table works.
Doing a second select the connection dies.
MariaDB [test]> select * from pivottet; ERROR 2013 (HY000): Lost connection to MySQL server during query
MariaDB [test]> create table pivottet engine=connect table_type=pivot tabname=salary; Query OK, 0 rows affected (0.02 sec) MariaDB [test]> select * from pivottet; +--------+------+-----+------+-----+ | sellet | 1 | 2 | 3 | 4 | +--------+------+-----+------+-----+ | 1 | 100 | 300 | 1000 | 0 | | 2 | 1000 | 100 | 0 | 0 | | 3 | 0 | 0 | 0 | 500 | +--------+------+-----+------+-----+ 3 rows in set (0.00 sec) MariaDB [test]> select * from pivottet; ERROR 2013 (HY000): Lost connection to MySQL server during query
That is written into the error log:
Jul 9 10:17:56 localhost mysqld: 130709 10:17:56 [Warning] Aborted connection 264 to db: 'test' user: 'root' host: 'localhost' (Unknown error)
Regards
Erkan
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Sorry erkan, I wrongly thought it was working on ubuntu but it turned
out that it did not and disconnected on the second,
and further, tries to select the table. So this is not closed but not
going to be solved soon because I get no information
on the possible error. For instance, under GDB nothing is told, and
looking at the traces I have done, mysqld disconnects
even before creating the CONNECT thread supposed to handle the query!
Because of this, and also on some valgring warnings, the next version of
CONNECT will not support the PIVOT type, hoping
that will be temporarily...
Regards,
Olivier
Is indeed failing on Linux
Further investigation shows that this bug is related to the use of the query cache. Before this is fixed (by preventing queries on PIVOT tables to be cached, as for queries on partitioned tables) a bypass is to specify the query_cache_size variable to 0. This makes the query cache not used.
Ahoi Olivier,
yes setting query_cache_size=0 worked.
Thx!
Because CONNECT works on external data that can be modified any time out of MariaDB, it must not use the query cache. Therefore, query cache has been permanently disabled for CONNECT tables.
I could not reproduce such error with the current version of CONNECT.
Do debug I need to know exactly what was executed and, in particular, to
have the salary table.
How can I get that from Erkan?
Regards, Olivier