Watch, Follow, &
Connect with Us

For forums, blogs and more please visit our
Developer Tools Community.


Welcome, Guest
Guest Settings
Help

Thread: DataSetProvider with poPropogateChanges & nested datasets


This question is not answered. Helpful answers available: 2. Correct answers available: 1.


Permlink Replies: 2 - Last Post: Apr 20, 2016 3:13 PM Last Post By: Mathias Burbach
Mathias Burbach

Posts: 42
Registered: 12/8/99
DataSetProvider with poPropogateChanges & nested datasets  
Click to report abuse...   Click to reply to this thread Reply
  Posted: Apr 18, 2016 3:25 AM
Hello Folks!

We are using the TDataSetProvider.Option poPropogateChanges to transport changes made by the application server back into the ClientDataSet on the client-side. In our case it is a version number called UpdNo, which gets incremented by the application server on each update. Now we have a rather complex structure, where we have hit the number of 17 nested datasets. We are running into an "Access violation at address 77A68DA9 in module 'ntdll.dll'" if we add more than 16 nested datasets. If we disable poPropogateChanges we can go beyond 16 nested datasets.

Stepping through the source code of TCustomResolver.InternalUpdateRecord I can see that the Tree.HasError becomes true after calling TCustomResolver.LogUpdateRecord (line 3414 of Datasnap.Provider.pas). But the same is true if the apply update is done with 16 nested datasets. So I have no idea why the access violation is raised with 17 nested datasets.

To make the problem reproducibly I have created a sample application using the employee InterBase database with 16 or 17 nested datasets and the option to switch on or off poPropogateChanges. The sample application can be downloaded from here:
http://www.maranatha-consulting.com/Delphi/TestPropogateChangesFDAC.zip
To mimic a side effect of applying an update I have increased the department budget by one dollar each time a record is updated.

I am looking forward to your suggestions on how to solve the problem.

Salut,
Mathias
Mathias Burbach

Posts: 42
Registered: 12/8/99
Re: DataSetProvider with poPropogateChanges & nested datasets  
Click to report abuse...   Click to reply to this thread Reply
  Posted: Apr 18, 2016 3:43 AM   in response to: Mathias Burbach in response to: Mathias Burbach
I forgot to mention:
It is Delphi 10 Seattle Architect we are using. But the same AV happens in Delphi XE7 too.

Salut,
Mathias

Edited by: Mathias Burbach on Apr 18, 2016 8:43 PM
Mathias Burbach

Posts: 42
Registered: 12/8/99
Re: DataSetProvider with poPropogateChanges & nested datasets  
Click to report abuse...   Click to reply to this thread Reply
  Posted: Apr 20, 2016 3:13 PM   in response to: Mathias Burbach in response to: Mathias Burbach
Hello Folks!

I have logged the problem in Embarcadero's JIRA service portal here:
https://quality.embarcadero.com/browse/RSP-14239

I would appreciate your votes! ;-)

Salut,
Mathias
Legend
Helpful Answer (5 pts)
Correct Answer (10 pts)

Server Response from: ETNAJIVE02