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

Wed Jun 3 05:19:04 PDT 2015

It now probably becomes a question for Stephan. See below.

On Tue, Jun 02, 2015 at 03:17:16PM +0200, Lionel Elie Mamane wrote:
> On Tue, Jun 02, 2015 at 03:12:51PM +0200, Noel Grandin wrote:

>> I would suggest something like this in ODriverDelegator::flushConnections():

>>     take_mutex();
>>     std::vector<Connection> tmp = m_aConnections;
>>     release_mutex();
>>     for (Connection conn : tmp)
>>         conn.flush();

>> so that the mutex is not held during the problematic phase

> That makes sense. Will try that. Thanks!

It does not solve my problem, because the same mutex is taken deeper
in the stack:

#23 0x00002abc1b1a9fd8 in connectivity::hsqldb::ODriverDelegator::preCommit (this=0x2d24ef0, aEvent=...)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/connectivity/source/drivers/hsqldb/HDriver.cxx:65
#24 0x00002abc18bb7081 in OStorage::BroadcastTransaction (this=this at entry=0x3578030, 
    nMessage=nMessage at entry=1 '\001')
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/package/source/xstor/xstorage.cxx:2094
#25 0x00002abc18bc66e3 in OStorage::commit (this=0x3578030)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/package/source/xstor/xstorage.cxx:3937
#26 0x00002abc13f336ad in dbaccess::tools::stor::commitStorageIfWriteable (
    _rxStorage=uno::Reference to (OStorage *) 0x3578038)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/dbaccess/source/core/misc/sdbcoretools.cxx:139
#27 0x00002abc13ef82cd in dbaccess::DocumentStorageAccess::commitEmbeddedStorage (this=0x35ba790, 
    _bPreventRootCommits=_bPreventRootCommits at entry=false)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/dbaccess/source/core/dataaccess/ModelImpl.cxx:290
#28 0x00002abc13efc0b2 in dbaccess::ODatabaseModelImpl::commitEmbeddedStorage (this=0x35bbd20, 
    _bPreventRootCommits=_bPreventRootCommits at entry=false)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/dbaccess/source/core/dataaccess/ModelImpl.cxx:887
#29 0x00002abc13eb58c8 in dbaccess::ODatabaseSource::flushed (this=0x35b7c60)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/dbaccess/source/core/dataaccess/datasource.cxx:1306
#30 0x00002abc13eae005 in dbaccess::FlushNotificationAdapter::flushed (this=0x318ec50, rEvent=...)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/dbaccess/source/core/dataaccess/datasource.cxx:172
(...)
#34 0x00002abc1b1a07f1 in connectivity::hsqldb::OHsqlConnection::flush (this=0x3577db0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/connectivity/source/drivers/hsqldb/HConnection.cxx:168
#35 0x00002abc1b1a9ba3 in connectivity::hsqldb::ODriverDelegator::flushConnections (this=0x2d24ef0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/connectivity/source/drivers/hsqldb/HDriver.cxx:629

But let's take it from the other side...

connectivity::hsqldb::ODriverDelegator::preCommit does:

654	Reference<XConnection> xConnection(i->first,UNO_QUERY);
655	if ( xConnection.is() )
656	{
657	      Reference< XStatement> xStmt = xConnection->createStatement();

Now, this goes through a whole rigmarole:

#6  0x00002abc1b6e90d3 in AffineBridge::v_callInto_v (this=0x2d29b50, pCallee=0x2abbf94eedbe <s_pull(va_list*)>, 
    pParam=0x2abc0fd9bdb0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/cppu/source/AffineBridge/AffineBridge.cxx:250
#7  0x00002abc1b6e9b07 in cppu::Enterable_call_callInto_v (context=0x2d29b50, 
    pCallee=0x2abbf94eedbe <s_pull(va_list*)>, pParam=0x2abc0fd9bdb0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/include/cppu/Enterable.hxx:69
#8  0x00002abc1b8eee97 in cppu::Enterable::callInto_v (this=0x2d29b50, 
    pCallee=pCallee at entry=0x2abbf94eedbe <s_pull(va_list*)>, pParam=pParam at entry=0x2abc0fd9bdb0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/include/cppu/Enterable.hxx:53
#9  0x00002abc1b8eeccf in Base::v_callInto_v (this=0x2d29eb0, pCallee=0x2abbf94eedbe <s_pull(va_list*)>, 
    pParam=0x2abc0fd9bdb0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/cppu/source/helper/purpenv/helper_purpenv_Environment.cxx:508
#10 0x00002abc1b8eef6f in cppu::Enterable_call_callInto_v (context=0x2d29eb0, 
    pCallee=0x2abbf94eedbe <s_pull(va_list*)>, pParam=0x2abc0fd9bdb0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/include/cppu/Enterable.hxx:69
#11 0x00002abbf94ef997 in cppu::Enterable::callInto_v (this=this at entry=0x2d29eb0, 
    pCallee=pCallee at entry=0x2abbf94eedbe <s_pull(va_list*)>, pParam=pParam at entry=0x2abc0fd9bdb0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/include/cppu/Enterable.hxx:53
#12 0x00002abbf94efaac in cppu::Enterable::callInto (this=this at entry=0x2d29eb0, 
    pCallee=pCallee at entry=0x2abbf94eedbe <s_pull(va_list*)>)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/include/cppu/Enterable.hxx:90
#13 0x00002abbf94eeeb4 in s_callInto_v (pEnv=pEnv at entry=0x2d29900, 
    pCallee=pCallee at entry=0x2abbf94ef0b9 <s_environment_invoke_vv(va_list*)>, pParam=pParam at entry=0x2abc0fd9bee0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/cppu/source/uno/EnvStack.cxx:233
#14 0x00002abbf94eef7e in s_callInto (pEnv=0x2d29900, 
    pCallee=pCallee at entry=0x2abbf94ef0b9 <s_environment_invoke_vv(va_list*)>)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/cppu/source/uno/EnvStack.cxx:244
#15 0x00002abbf94ef316 in s_environment_invoke_v (pCurrEnv=0x0, pTargetEnv=pTargetEnv at entry=0x2d29900, 
    pCallee=pCallee at entry=0x2abc1b8f07c6 <s_dispatcher_v(va_list*)>, pParam=pParam at entry=0x2abc0fd9c050)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/cppu/source/uno/EnvStack.cxx:300
#16 0x00002abbf94ef384 in uno_Environment_invoke_v (pTargetEnv=pTargetEnv at entry=0x2d29900, 
    pCallee=pCallee at entry=0x2abc1b8f07c6 <s_dispatcher_v(va_list*)>, pParam=pParam at entry=0x2abc0fd9c050)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/cppu/source/uno/EnvStack.cxx:312
#17 0x00002abbf94ef456 in uno_Environment_invoke (pEnv=0x2d29900, 
    pCallee=0x2abc1b8f07c6 <s_dispatcher_v(va_list*)>)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/cppu/source/uno/EnvStack.cxx:321
#18 0x00002abc1b8f0ccc in Proxy::dispatch (this=this at entry=0x3577660, 
    pReturnTypeRef=pReturnTypeRef at entry=0x3023920, pParams=pParams at entry=0x0, nParams=nParams at entry=0, 
    pMemberType=pMemberType at entry=0x3436a40, pReturn=pReturn at entry=0x2abc0fd9c2f0, pArgs=0x2abc0fd9c2e0, 
    ppException=0x2abc0fd9c390)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/cppu/source/helper/purpenv/helper_purpenv_Proxy.cxx:445
#19 0x00002abc1b8efc7d in s_Proxy_dispatch (pUnoI=0x3577660, pMemberType=pMemberType at entry=0x3436a40, 
    pReturn=pReturn at entry=0x2abc0fd9c2f0, pArgs=pArgs at entry=0x2abc0fd9c2e0, 
    ppException=ppException at entry=0x2abc0fd9c390)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/cppu/source/helper/purpenv/helper_purpenv_Proxy.cxx:170
#20 0x00002abc0f3f1fd2 in cpp2uno_call (pThis=pThis at entry=0x2d2ca80, pMemberTypeDescr=0x3436a40, 
    pReturnTypeRef=pReturnTypeRef at entry=0x3023920, nParams=nParams at entry=0, pParams=pParams at entry=0x0, 
    gpreg=0x2abc0fd9c720, gpreg at entry=0x2abc0fd9c710, fpreg=0x2abc0fd9c740, ovrflw=0x2abc0fd9c790, 
    pRegisterReturn=0x2abc0fd9c6f0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/bridges/source/cpp_uno/gcc3_linux_x86-64/cpp2uno.cxx:186
#21 0x00002abc0f3f2a6a in cpp_vtable_call (nFunctionIndex=<optimized out>, nVtableOffset=0, 
    gpreg=0x2abc0fd9c710, fpreg=0x2abc0fd9c740, ovrflw=0x2abc0fd9c790, pRegisterReturn=0x2abc0fd9c6f0)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/bridges/source/cpp_uno/gcc3_linux_x86-64/cpp2uno.cxx:377
#22 0x00002abc0f409c12 in privateSnippetExecutor ()
   from /home/master/src/libreoffice/workdirs/libreoffice-5-1/instdir/program/libgcc3_uno.so
#23 0x00002abc1b1a9fd8 in connectivity::hsqldb::ODriverDelegator::preCommit (this=0x2d24ef0, aEvent=...)
    at /home/master/src/libreoffice/workdirs/libreoffice-5-1/connectivity/source/drivers/hsqldb/HDriver.cxx:657
#24 0x00002abc18bb7081 in OStorage::BroadcastTransaction (this=this at entry=0x3578030, 

The problem is essentially the serializing that happens at
AffineBridge::v_callInto_v.

Now, I guess that the whole privateSnippetExecutor / cpp_vtable_call /
cpp2uno_call / s_Proxy_dispatch / ... / AffineBridge::v_callInto_v for
a C++-to-C++ call is somehow linked to the fact that the calling code
does not know the object that implements the XConnection
interface. Can I avoid it in some way? For example, I *know* that
m_xConnection is a connectivity::java_sql_connection.

If I use that fact, can I avoid going through AffineBridge::v_callInto_v ?

-- 
Lionel