RE: (forte-users) FW: (forte-users)

Question

Hi there
Thanks very much for the solution - just wanted to let you know . We
implemented the design that technote 11378 suggested .
It worked .
Thanks very much
Cheers
Jen
-----Original Message-----
From: Adamek, Zenon [mailto:ZAdamekpurolator.com]
Sent: Tuesday, 20 March, 2001 9:21 PM
To: 'forte-userslists.xpedior.com'
Subject: (forte-users) FW: (forte-users)
Hi David,
The problem is that the SO uses an attribute of its class ACBAccount as
the ObjectReference pointer. SO is not a stateless object. The possible
scenario before crash can be that client A and B calls SO at the same
time. A's thread creates ACBAccount gets the ObjectReference. At this
point B's thread is activated, does the same as A creates new
ObjectReference. Probably the next switch between A and B will be in the
Connect() (B should wait for OLE server). If A is reactivated it doesn't
get the original own reference but the B's reference. It can cause the
crash and means that a thread can use reference created in some other
thread.
Regards,
Zenon
-----Original Message-----
From: David McPaul [SMTP:dmcpaullumley.com.au]
Sent: Monday, March 19, 2001 11:52 PM
To: 'forte-userslists.xpedior.com'
Subject: RE: (forte-users)
Jenni,
As Zenon has pointed out, technote 11378 talks about problems that
can occur if the calls made to an OLE object are not from within the same
thread the OLE object was created in. It goes on to show a design to
avoid
this.
However, the code you have given DOES communicate to the OLE object
in the same thread as it was created. So the problem as I see it is more
likely to be that the OLE object is not being garbage collected. Although
you do explicitly NIL out the ACBAccount object there is a technote 12453
that deals with the need to set the ObjectReference of CDispatch objects
to
NIL to allow the OLE object to be completely reclaimed by the garbage
collector. Failure to do so when using code that creates a new OLE object
every time you ask for an account validation will eventually run the
partition out of memory.
As pointed out in a previous post you can also increase
FORTE_STACK_SIZE but this will delay the problem not correct it.
Rather than create the connection each time you may want to think
about redesigning the method as shown in tech note 11378.
Cheers
David
-----Original Message-----
From: Adamek, Zenon [mailto:ZAdamekpurolator.com]
Sent: Tuesday, March 20, 2001 5:05 AM
To: 'Els, Jenni'
Cc: 'forte-userslists.xpedior.com'
Subject: RE: (forte-users)
Hi Jenni,
The most important issue by designing an OLE connection between a Forte
server partition and an OLE component is taking into account that an OLE
object can be referenced from the NT thread in Forte partition that it was
created in. It is the reason that you have no problems with your mini-app
in
single-threaded version.
This problem is discussed in the Technote 11378. You can find a workaround
for your problem there, too.
Regards,
Zenon
-----Original Message-----
From: Els, Jenni [SMTP:JElsnbs.co.za]
Sent: Monday, March 19, 2001 2:28 AM
To: 'forte-userslists.xpedior.com'
Subject: (forte-users)
Hi there
We have this situation
We are calling a Service Object (in the server partition) from ourclient
partition.This service object calls a method which calls a DLLregistered
on our server (VB code) . This VB code access a database on anotherserver
.(DSN set up on our server ).The database is sql server .
We are having the problem where for about 3 hours in the morning , the
system works perfectly. We then get a segmentation violation on this
partition . When we run interpreted we can see that this is an OLEinvoked
exception. The partition does not always show as offline in econsole
and
because it does not , we cannot 'online' another . We cannot take the
entire app down as everything hangs . Eventually our technical depthas
to
down the server
We set up a mini-app looping through and calling the DLL to simulate
the
problem . It worked fine. When we put another asynchronous task in the
method to call the service object , it erred quite soon. We thencreate
an
attribute of type mutex and locked using that. The mini-app worked.
However our app in development eventually hanged (without the
partition
coming though) .
The service Object is an environment visible service object in asingle
(non-replicated partition) . It has a dialog duration = session .
In the project is
ACB : ACBObject
ACBObject : CDispatch (shared = disallowed , distributed =
disallowed, transactional = disallowed, monitored = allowed)
ACBValidator : Object (shared = allowed , distributed =allowed,
transactional = disallowed, monitored = disallowed)
ACBVaidatorSO : ACBValidator
In this method we have this code to call the DLL
self.ACBAccount = new;
self.ACBAccount.CreateUsingCLSID(classID='{2EFD3084-7B05-11D3-857F-00105A4
8CEA0}');
pErrorMessage = new;
acbaccount.BankCode = pBankCode.value;
acbaccount.BranchCode = pBranchCode.value;
at : VariantI2 = new;
at.Value = pAccountType.Value;
acbaccount.AccountType = at.Value;
acbaccount.AccountNo = pAccountNo.value;
begin
acbaccount.Connect();
exception
when e : GenericException do
ex : GenericException = new;
ex.SetWithParams(severity = SP_ER_ERROR,
message = 'There was an error connecting to the database');
raise ex;
end;
begin
err : i2 = acbaccount.ValidateAccount();
if err != 0 then
pErrorMessage.SetValue(acbaccount.ErrDescriptionStr(iErrorCode= err));
acbaccount.Disconnect();
return false;
else
pErrorMessage.SetValue('The account is
valid!!');
acbaccount.Disconnect();
self.ACBAccount = NIL ;
return true;
end if;
exception
when e : GenericException do
acbaccount.Disconnect();
ex : GenericException = new;
ex.SetWithParams(severity = SP_ER_ERROR,
message = 'There was an error Validating the account');
Task.ErrorMgr.AddError(ex);
task.errormgr.ShowErrors();
raise e;
end;
exception
when e : GenericException do
acbaccount.Disconnect();
Task.ErrorMgr.ShowErrors();
raise e;
If anybody has any suggestions , they would be most welcome
Thanks very much
Cheers
Jenni Els************************************************************************Th
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Answer 1

Hi there
Thanks very much for the solution - just wanted to let you know . We
implemented the design that technote 11378 suggested .
It worked .
Thanks very much
Cheers
Jen
-----Original Message-----
From: Adamek, Zenon [mailto:ZAdamekpurolator.com]
Sent: Tuesday, 20 March, 2001 9:21 PM
To: 'forte-userslists.xpedior.com'
Subject: (forte-users) FW: (forte-users)
Hi David,
The problem is that the SO uses an attribute of its class ACBAccount as
the ObjectReference pointer. SO is not a stateless object. The possible
scenario before crash can be that client A and B calls SO at the same
time. A's thread creates ACBAccount gets the ObjectReference. At this
point B's thread is activated, does the same as A creates new
ObjectReference. Probably the next switch between A and B will be in the
Connect() (B should wait for OLE server). If A is reactivated it doesn't
get the original own reference but the B's reference. It can cause the
crash and means that a thread can use reference created in some other
thread.
Regards,
Zenon
-----Original Message-----
From: David McPaul [SMTP:dmcpaullumley.com.au]
Sent: Monday, March 19, 2001 11:52 PM
To: 'forte-userslists.xpedior.com'
Subject: RE: (forte-users)
Jenni,
As Zenon has pointed out, technote 11378 talks about problems that
can occur if the calls made to an OLE object are not from within the same
thread the OLE object was created in. It goes on to show a design to
avoid
this.
However, the code you have given DOES communicate to the OLE object
in the same thread as it was created. So the problem as I see it is more
likely to be that the OLE object is not being garbage collected. Although
you do explicitly NIL out the ACBAccount object there is a technote 12453
that deals with the need to set the ObjectReference of CDispatch objects
to
NIL to allow the OLE object to be completely reclaimed by the garbage
collector. Failure to do so when using code that creates a new OLE object
every time you ask for an account validation will eventually run the
partition out of memory.
As pointed out in a previous post you can also increase
FORTE_STACK_SIZE but this will delay the problem not correct it.
Rather than create the connection each time you may want to think
about redesigning the method as shown in tech note 11378.
Cheers
David
-----Original Message-----
From: Adamek, Zenon [mailto:ZAdamekpurolator.com]
Sent: Tuesday, March 20, 2001 5:05 AM
To: 'Els, Jenni'
Cc: 'forte-userslists.xpedior.com'
Subject: RE: (forte-users)
Hi Jenni,
The most important issue by designing an OLE connection between a Forte
server partition and an OLE component is taking into account that an OLE
object can be referenced from the NT thread in Forte partition that it was
created in. It is the reason that you have no problems with your mini-app
in
single-threaded version.
This problem is discussed in the Technote 11378. You can find a workaround
for your problem there, too.
Regards,
Zenon
-----Original Message-----
From: Els, Jenni [SMTP:JElsnbs.co.za]
Sent: Monday, March 19, 2001 2:28 AM
To: 'forte-userslists.xpedior.com'
Subject: (forte-users)
Hi there
We have this situation
We are calling a Service Object (in the server partition) from ourclient
partition.This service object calls a method which calls a DLLregistered
on our server (VB code) . This VB code access a database on anotherserver
.(DSN set up on our server ).The database is sql server .
We are having the problem where for about 3 hours in the morning , the
system works perfectly. We then get a segmentation violation on this
partition . When we run interpreted we can see that this is an OLEinvoked
exception. The partition does not always show as offline in econsole
and
because it does not , we cannot 'online' another . We cannot take the
entire app down as everything hangs . Eventually our technical depthas
to
down the server
We set up a mini-app looping through and calling the DLL to simulate
the
problem . It worked fine. When we put another asynchronous task in the
method to call the service object , it erred quite soon. We thencreate
an
attribute of type mutex and locked using that. The mini-app worked.
However our app in development eventually hanged (without the
partition
coming though) .
The service Object is an environment visible service object in asingle
(non-replicated partition) . It has a dialog duration = session .
In the project is
ACB : ACBObject
ACBObject : CDispatch (shared = disallowed , distributed =
disallowed, transactional = disallowed, monitored = allowed)
ACBValidator : Object (shared = allowed , distributed =allowed,
transactional = disallowed, monitored = disallowed)
ACBVaidatorSO : ACBValidator
In this method we have this code to call the DLL
self.ACBAccount = new;
self.ACBAccount.CreateUsingCLSID(classID='{2EFD3084-7B05-11D3-857F-00105A4
8CEA0}');
pErrorMessage = new;
acbaccount.BankCode = pBankCode.value;
acbaccount.BranchCode = pBranchCode.value;
at : VariantI2 = new;
at.Value = pAccountType.Value;
acbaccount.AccountType = at.Value;
acbaccount.AccountNo = pAccountNo.value;
begin
acbaccount.Connect();
exception
when e : GenericException do
ex : GenericException = new;
ex.SetWithParams(severity = SP_ER_ERROR,
message = 'There was an error connecting to the database');
raise ex;
end;
begin
err : i2 = acbaccount.ValidateAccount();
if err != 0 then
pErrorMessage.SetValue(acbaccount.ErrDescriptionStr(iErrorCode= err));
acbaccount.Disconnect();
return false;
else
pErrorMessage.SetValue('The account is
valid!!');
acbaccount.Disconnect();
self.ACBAccount = NIL ;
return true;
end if;
exception
when e : GenericException do
acbaccount.Disconnect();
ex : GenericException = new;
ex.SetWithParams(severity = SP_ER_ERROR,
message = 'There was an error Validating the account');
Task.ErrorMgr.AddError(ex);
task.errormgr.ShowErrors();
raise e;
end;
exception
when e : GenericException do
acbaccount.Disconnect();
Task.ErrorMgr.ShowErrors();
raise e;
If anybody has any suggestions , they would be most welcome
Thanks very much
Cheers
Jenni Els************************************************************************Th
is e-mail is intended for the use of the individual or entity named above
and may contain information that is confidential and privileged. If you
are not the intended recipient, you are hereby notified that any
dissemination, distribution or copying of this e-mail is strictly
prohibited. If you have received this e-mail in error, please notify us
immediately at helpdesklumley.com.au and destroy the original message.
While this mail and any attachments have been scanned for common computer
viruses and found to be virus free, we recommend you also perform your own
virus checking processes before opening any attachments.
For the archives, go to: http://lists.xpedior.com/forte-users and use
the login: forte and the password: archive. To unsubscribe, send in a new
email the word: 'Unsubscribe' to: forte-users-requestlists.xpedior.com--
For the archives, go to: http://lists.xpedior.com/forte-users and use
the login: forte and the password: archive. To unsubscribe, send in a new
email the word: 'Unsubscribe' to: forte-users-requestlists.xpedior.com
WARNING:
Any unauthorised use or interception of this email is illegal. If this email
is not intended for you, you may not copy, distribute nor disclose the
contents to anyone. Save for bona fide company matters, the BoE Group does
not accept any responsibility for the opinions expressed in this email.
For further details please see: http://www.nbs.co.za/emaildisclaim.htm