MySQL Bugs: #64466: Myodbc linux: Error in my_thread_global

Bug #64466	Myodbc linux: Error in my_thread_global_end() and threads
Submitted:	27 Feb 2012 11:58	Modified:	23 Apr 4:37
Reporter:	Pierre MARC	Email Updates:
Status:	Can't repeat	Impact on me:	None
Category:	Connector / ODBC	Severity:	S1 (Critical)
Version:	05.01.0010	OS:	Linux (Not tested on other OS)
Assigned to:	Bogdan Degtyariov	CPU Architecture:	Any
Tags:	my_thread_global_end, MyODBC, threads

Description:
When we open a connection from one thread and close it from another thread we get the message:

Error in my_thread_global_end(): 1 threads didn't exit

We don’t know what are the consequences of this situation but I’m afraid that it produces some kind of instability and/or memory leak.

We use the odbc driver with a framework that creates pool of connections and several threads can access the odbc connection (one at a time because its synchronized). Sometimes because of time outs, the connection needs to be closed and reopened by the thread. So this bug is for us a blocking situation.

Attached is a simple program that reproduces the issue. Just compile it on linux. The usage is:

testodbc2 -s DataSource -u User [-p Password]

Here is the report on my test machine:

Open db source TEST from thread 1720362784
Source successfully connected
Database name: MySQL
Database version: 5.0.51a-community-nt-log
Driver name: libmyodbc5.so
Driver version: 05.01.0010
Driver ODBC version: 03.52
Close db source from thread 1685018368
Error in my_thread_global_end(): 1 threads didn't exit
Source successfully disconnected

I tried with a 3.51 driver and the result is the same.

How to repeat:
Open a connection from one thread and close it from another thread. The attached source file reproduces the issue.
The usage is:

testodbc2 -s DataSource -u User [-p Password]

Here is the report on my test machine:

Open db source TEST from thread 1720362784
Source successfully connected
Database name: MySQL
Database version: 5.0.51a-community-nt-log
Driver name: libmyodbc5.so
Driver version: 05.01.0010
Driver ODBC version: 03.52
Close db source from thread 1685018368
Error in my_thread_global_end(): 1 threads didn't exit
Source successfully disconnected

Small program that reproduces the issue (tried on linux)

Attachment: testodbc2.zip (application/x-zip-compressed, text), 2.48 KiB.

Isn't it a server bug (fixed in 5.0.70+)? See bug #37226.

I dont think this is the same bug. The bug #37226 was a windows one and for libmysql not for the odbc connector. The bug I reported occurs on the last version of the linux odbc connector. The program I attached to the case reproduces it. I got this bug on 32 and 64 bit linux machines.

Verified

Seeing this on MacOSX 10.4.11/ppc with a self-built v5.1.10 connector.

We have the same bug with more recent versions of MySQL. We used a custom-compiled unixODBC 2.3.1 on Open Suse 11.3 to reproduce the issue. Here is the report as generated by Pierre's program:

Open db source MySQL R&D test database from thread -1346640096
Source successfully connected
Database name: MySQL
Database version: 5.0.87-community
Driver name: libmyodbc5w.so
Driver version: 05.02.0004
Driver ODBC version: 03.52
Close db source from thread -1387923712
Error in my_thread_global_end(): 1 threads didn't exit
Source successfully disconnected

Program terminated successfully

Is there any update on this bug?
I can confirm this issue still exists with MySQL drivers in versions 5.1.13 and 5.2.7. on SLES11.

Hello,

I tested with the last driver and seems the issues is still there ?
Any idea when a fix will be available ? Or what effects has this bug over a production system ? memory leaks, crashes ?

Output is here:

./testodbc2 -s test
Open db source test from thread 1259255616
Source successfully connected
Database name: MySQL
Database version: 5.6.26-74.0-56
Driver name: libmyodbc5w.so
Driver version: 05.03.0004
Driver ODBC version: 03.52
Close db source from thread 1214273280
Error in my_thread_global_end(): 1 threads didn't exit
Source successfully disconnected

Silviu

Posted by developer:
 
The bug is no longer repeatable with ODBC driver version 8.4.0:

Open db source test from thread -351987904
Source successfully connected
Database name: MySQL
Database version: 8.3.0-commercial
Driver name: libmyodbc8w.so
Driver version: 08.04.0000
Driver ODBC version: 03.52
Close db source from thread -387975488
Source successfully disconnected

Closing the ticket.