[MDEV-2752] LP:628780 - Connection loss on SELECT from empty table Created: 2010-09-08  Updated: 2015-02-02  Resolved: 2012-10-04

Status: Closed
Project: MariaDB Server
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Bug Priority: Major
Reporter: Heinz Wiesinger (Inactive) Assignee: Unassigned
Resolution: Not a Bug Votes: 0
Labels: Launchpad

Attachments: XML File LPexportBug628780.xml     File LPexportBug628780_oqgraph_testcase.sql    

 Description   

I'm using oqgraph trunk (revision 10) from launchpad with MariaDB 5.1.47. When executing the queries in the attached testcase, I get following response after the SELECT:

ERROR 2013 (HY000): Lost connection to MySQL server during query

      • Note from Arjen: this only happens when using code from the oqgraph repo, the bug not does not appear when building MariaDB 5.2 which includes oqgraph.

 Comments   
Comment by Heinz Wiesinger (Inactive) [ 2010-09-02 ]

Re: Connection loss on SELECT from empty table

Comment by Heinz Wiesinger (Inactive) [ 2010-09-02 ]

oqgraph_testcase.sql
LPexportBug628780_oqgraph_testcase.sql

Comment by Arjen Lentz (Inactive) [ 2010-09-08 ]

Re: Connection loss on SELECT from empty table
Heinz, since you're building from source anyway, can you please try this in MariaDB 5.2 which has OQGRAPH in the trunk already? I think you might be tripping over a bug that's already been fixed since, but not quite sure because of the different repos. thanks.

Comment by Heinz Wiesinger (Inactive) [ 2010-09-08 ]

Re: Connection loss on SELECT from empty table
I tried with latest 5.2 code. After some issues with xtradb vs. innodb I have it up and running just fine, but when trying to load the oqgraph engine I get an error:

[ERROR] Can't open shared library '/usr/lib64/mysql/plugin/oqgraph_engine.so' (errno: 0 undefined symbol: ZTVN10cxxabiv120_si_class_type_infoE)

I tried to google and found that it might have something to do with libstdc++. But that's about it :-/

Comment by Heinz Wiesinger (Inactive) [ 2010-09-08 ]

Re: Connection loss on SELECT from empty table
Ok, apparently that's an issue with oqgraph_engine.so not linking with libstdc++ in some cases. I had to specify g++ as my compiler instead of gcc to fix it.

Anyway, with the engine now loading I can verify that I no longer get that error on the oqgraph version included in MariaDB 5.2.

Comment by Arjen Lentz (Inactive) [ 2010-09-08 ]

Re: Connection loss on SELECT from empty table
Yep you need to build with g++. The scripts in BUILD/ do that, so please do use those.

Ok, thanks for verifying that indeed that issues has been fixed in the MariaDB oqgraph codebase. Will need to see why it's not in the oqgraph bzr repo... to prevent others from tripping over it.

Comment by Rasmus Johansson (Inactive) [ 2010-09-08 ]

Launchpad bug id: 628780

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