help needed: hsqldb shutdown race condition, how to fix without deadlock

[Michael Stahl]

On 09.06.2015 14:33, Lionel Elie Mamane wrote:
> On Wed, Jun 03, 2015 at 11:08:36PM +0200, Michael Stahl wrote:
>> On 03.06.2015 17:31, Lionel Elie Mamane wrote:
>>> On Wed, Jun 03, 2015 at 03:01:39PM +0200, Michael Stahl wrote:
>>>> On 03.06.2015 14:47, Lionel Elie Mamane wrote:
> 
>>>>> Since the problem is essentially that the two threads take the same mutexes
>>>>> in different order, here is a dirty hack that forces the hsqldb thread
>>>>> to take the "affine bridge" mutex before taking the "HSQL driver"
>>>>> mutex.
> 
>>>> i'm not entirely sure this is sensible...
> 
>>> Thinking the issue from yet another angle, if we go back to the
>>> situation at the start of this thread (hsqldb is *not* affine). I
>>> don't understand why the
>>> connectivity::hsqldb::ODriverDelegator::disposing thread holds the
>>> affine lock, and goes through the affine bridge:
> 
>>> Why does the call from dbaccess::OConnection::disposing into
>>> connectivity::hsqldb::ODriverDelegator::disposing go through the
>>> affine bridge?
> 
>> because OConnection is outside the affine environment, so it has to go
>> through the bridge to call a component inside the affine environment.
> 
>> however the ODriverDelegator isn't inside the affine environment, what
>> happens is that while AffineBridge::v_callInto_v() waits for the call on
>> the "inner" thread to return, it assigns the current (calling) thread as
>> the "outer" thread and in AffineBridge::outerDispatch() it waits for
>> outgoing calls from the "inner" thread.
> 
> You discuss what happens when the call goes into the affine bridge. I
> don't understand why it goes through the affine brige in the first
> place.

presumably because OConnection::disposing() is calling XConnection
methods that are implemented by class java_sql_Connection in the JDBC
driver.