[unixODBC-support] locking issue

Chauhan Bhavik-A20762 bhavik at motorola.com
Thu Dec 20 14:36:45 GMT 2007


Hi Nick,

This problem is faced when mysql server is reaching to 99.9 % of CPU
utilization. And all the threads within process is blocked with the same
stack as follow, then when the server is restarted it it's keeping up
the processing.

What could be the reason to be blocked?

#0  0x005ec7a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
#1  0x0085513e in __lll_mutex_lock_wait () from /lib/tls/libpthread.so.0
#2  0x00851d9b in _L_mutex_lock_35 () from /lib/tls/libpthread.so.0
#3  0xb73d1bf8 in ?? ()
#4  0x009edbfc in ?? () from /usr/lib/libodbc.so.1
#5  0x08121c00 in vtable for stbcidThreadFIFO ()
#6  0x90d75030 in ?? ()
#7  0xb73d1bf8 in ?? ()
#8  0x009d254a in SQLTablesW () from /usr/lib/libodbc.so.1
#9  0x009d254a in SQLTablesW () from /usr/lib/libodbc.so.1
#10 0x009adfbb in SQLGetData () from /usr/lib/libodbc.so.1

Or 

#0  0x005ec7a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
#1  0x0085513e in __lll_mutex_lock_wait () from /lib/tls/libpthread.so.0
#2  0x00851d9b in _L_mutex_lock_35 () from /lib/tls/libpthread.so.0
#3  0xb69d0fb8 in ?? ()
#4  0x009edbfc in ?? () from /usr/lib/libodbc.so.1
#5  0x08121c00 in vtable for stbcidThreadFIFO ()
#6  0x90dbb328 in ?? ()
#7  0xb69d0fb8 in ?? ()
#8  0x009d254a in SQLTablesW () from /usr/lib/libodbc.so.1
#9  0x009d254a in SQLTablesW () from /usr/lib/libodbc.so.1
#10 0x009b72b9 in SQLRowCount () from /usr/lib/libodbc.so.1


Regards,
Bhavik

-----Original Message-----
From: unixodbc-support-bounces at easysoft.com
[mailto:unixodbc-support-bounces at easysoft.com] On Behalf Of Nick Gorham
Sent: Thursday, December 20, 2007 7:27 PM
To: Support for the unixODBC project
Subject: Re: [unixODBC-support] locking issue

Chauhan Bhavik-A20762 wrote:

>Hi
>
> 
>
>In middle of run the process resulted in deadlock 
>
>Following is the stack got after doing pstack to the process which uses
>unixODBC 
>
> 
>
>Does SQLRowCount result in lock? 
>  
>
All ODBC calls lock to protect the ODBC structures, but it shoulkd never

cause a deadlock. Have you got "Threading=0" in the odbcinst,ini entry?

>And what SQLTablesW  means?
>
>  
>
It noprmally means you have linked to a non debug version and the 
debugger is having problems naming the functions.

-- 
Nick Gorham
Easysoft Limited
http://www.easysoft.com, http://www.unixODBC.org

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