Details
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Type:
Bug
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Status: Closed
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Priority:
Critical
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Resolution: Fixed
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Affects Version/s: None
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Fix Version/s: None
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Component/s: None
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Labels:
Description
Thank you for MariaDB 5.3.5-ga
The attached file contains a reproducer.
Running against 5.3.5-ga and a pull from bzr against 5.3 yesterday I am able to get mysqld to consume a great deal of memory by running the attached file thus:
mysql -D test < 20120313_mariadb_5_3_5_out_of_mem.sql
When memory is exhausted the error reported to the client is:
- ERROR 5 (HY000): Out of memory (Needed [digit] bytes)
and the server error log has:
[ERROR] mysqld: Out of memory (Needed [digit] bytes)
[ERROR] Out of memory; check if mysqld or some other process uses all available memory; if not, you may have to use 'ulimit' to allow mysqld to use more memory or you can add more swap space
(I am aware the query should avoid using single quotes around ints.)
Running bzr pull on:
Linux 2.6.32-131.6.1.el6.x86_64 #1 SMP x86_64 x86_64 x86_64 GNU/Linux
Using mariadb-5.3.5-ga-Linux-x86_64.tar.gz on:
Linux l2.6.32-220.el6.x86_64 #1 SMP x86_64 x86_64 x86_64 GNU/Linux
Cheers
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Re: Query casues excessive memory consumption
BTW, All such recursive calls should check stack overflow (it is not cause of the problem but could be in theory).
Re: Query casues excessive memory consumption
in 5.2 tree_or() looks like this:
tree_or()
{
...
if (sel_trees_can_be_ored())
else
{ // everything else }
return;
}
in 5.3 it is
tree_or()
{
...
if (sel_trees_can_be_ored())
{ ... }
// everything else including allocating new objects
return;
}
Re: Query casues excessive memory consumption
The above change was done by WL#24: "index_merge: fair choice between index_merge union and range access"
Re: Query casues excessive memory consumption
Thank you very much. I can confirm the fix stops the problem using the isolated reproducers I have. I am holding off retesting MariaDB 5.3 with the actual database where this problem was found because https://bugs.launchpad.net/maria/+bug/954900 was found in the same database.
Launchpad bug id: 954262
20120313_mariadb_5_3_5_out_of_mem.sql
LPexportBug954262_20120313_mariadb_5_3_5_out_of_mem.sql