OracleSessionPool, AV while destroying datamodule

[ldsandon]

I am getting AVs while destroying a datamodule with a session pool component on it - it started giving me AVs when I added the pool. Is there any issue to be aware of while destroying a pool - i.e. or session must be logged out - ?

 

[Marco Kalter]

I'm not aware of any problem. When a session pool is destroyed, it will disconnect all sessions that are connected through the pool.

If you have a little project that reproduces this, please send it to me.

 

[ldsandon]

I will try to reproduce it in a small test case, by now I found - looking at the CPU window - that the AV occurs in TOracleSessionPool.Release, I think when it calls TOracleSessionPool.GetEntry, but looking at machine code is a bit difficult to undertand why.

 

[ldsandon]

I have additional infos, it looks to be a strange bug.

I was trying to parse an XML file (which holds a "master" and "detail" records") and write it to a database. First I tried using Datasmap and XMLTransforms, then did it manually because the XML transformations have problems with more than one nested dataset.

I wrote something like this to process XML subnodes (mapping them to detail tables):

SubNode := MailNode.ChildNodes.FindNode('ATTACHMENTS');
if (SubNode <> nil) and SubNode.HasChildNodes then
begin
  for j := 0 to SubNode.ChildNodes.Count -1 do
  begin
    dsAttachments.Insert;
    dsAttachmentsCONTENT_TYPE.AsVariant := SubNode.ChildNodes[j]['CONTENT_TYPE'];
    dsAttachmentsFILENAME.AsVariant := SubNode.ChildNodes[j]['FILE'];
    dsAttachmentsELEMENT_ID.AsVariant := SubNode.ChildNodes[j]['ELEMENT_ID'];
    dsAttachments.Post;
  end;
end;

I was using TOracleDataset because I used them before with Datasnap, they were set for a M/D relationship therefore I relied on them to generate PKs (using sequences) and FKs (using the M/D relationship).

I discovered that sometimes - not always - when calling Post an "Index list out of bound (-2)" exception was raised, and from now on attempting to close the TOracleSession used by that dataset would result in an AV.

When I got rid of all the dataset and rewrote it to use plain TOracleQuery components, the error disappeared. Yet I wonder why it appeared, because the logic it's the same, the difference is now I don't rely on components to generate and set PKs and FKs but do it myself in code.

 

[Marco Kalter]

Do you know where the "list index out of bounds" occurred? Was it is your own code or in a Direct Oracle Access unit?

 

[ldsandon]

The exception is raised when I call TOracleDataset.Post, and it looks to happen in DOA code, but I do not have the sources thus I can't check where it really happens. NOw I rewrote everything to avoid this error, but I could get the old code from CVS and send to you.

 

[Marco Kalter]

If you still have the source code, it would be nice to have it.

 

[ldsandon]

I got the code from CVS, hope all files are the same rev because I didn't tag them. How can I send them to you?

 

[Marco Kalter]

You can send them by e-mail to support@allroundautomations.com.