John


I was actually thinking of a separate micro app to do the extract and restore.

Roy Lambert [Team Elevate]

John,

<< After upgrading the table, I'm reading each record saving the blob field
to a zip file, unzipping the file, clearing the blob field then reloading it
with the unzipped file, then call .post on the table and that is where the
crash occurs. >>

I'm finishing up ElevateDB 2.05 this morning, but let me do some more
playing around with this today and see if I can reproduce the problem here.
It sounds a lot like this incident report:

http://www.elevatesoft.com/incident?action=viewrep&category=dbisam&release=4.28&incident=3037

But it occurred with deletes, and you're not deleting the records, just
clearing the BLOB field(s).

--
Tim Young
Elevate Software
www.elevatesoft.com

Thanks Tim, looking forward to your further comments

John

"Tim Young [Elevate Software]" <timyoung@elevatesoft.com> wrote in message
news:A7BA47F6-552B-469B-AE46-AF785C4124C5@news.elevatesoft.com...
> John,
>
> << After upgrading the table, I'm reading each record saving the blob
> field to a zip file, unzipping the file, clearing the blob field then
> reloading it with the unzipped file, then call .post on the table and that
> is where the crash occurs. >>
>
> I'm finishing up ElevateDB 2.05 this morning, but let me do some more
> playing around with this today and see if I can reproduce the problem
> here. It sounds a lot like this incident report:
>
> http://www.elevatesoft.com/incident?action=viewrep&category=dbisam&release=4.28&incident=3037
>
> But it occurred with deletes, and you're not deleting the records, just
> clearing the BLOB field(s).
>
> --
> Tim Young
> Elevate Software
> www.elevatesoft.com

John,

<< Thanks Tim, looking forward to your further comments >>

Okay, sorry about the delay.  Before you reload the BLOBs, are you altering
the table to make the BLOB field use compression ?  Because, if not, then
you could end up drastically increasing the size of the BLOBs on disk.

The test I'm running here seems to work okay.  What I'm doing is initially
populating a table's BLOB field with about 2.5GB of data.  The table has a
BLOB block size of 32768 bytes (32KB).  Then, I'm running through the table
with this code:

     First;
     while (not EOF) do
        begin
        Edit;
        TempBlobSize:=biolifeNotes.BlobSize;
        biolifeNotes.SaveToFile('c:\temp\dummy.txt');
        biolifeNotes.Clear;
        biolifeNotes.AsString:=RandomString((TempBlobSize+Integer(TempBlobSize
div 2)));
        Post;
        Label1.Caption:=biolifeSpeciesNo.AsString;
        Label1.Update;
        Next;
        end;

which simulates both saving the BLOB to disk, clearing the BLOB, and then
re-populating the BLOB with a new string that is (at most) 50% larger than
the previous size of the BLOB.  This simulates expanding the size of the
BLOB for each record.

--
Tim Young
Elevate Software
www.elevatesoft.com

Tim,

Not altering the table at all.  The table is a v3 table that does not use
blob compression and that has been upgraded to version 4 using
sql 'upgrade table'.  Then just step through the table and save the blob
field to a file, clear the blob field then reload the blob field
with the file (after unzipping).

I have reworked the procedure to avoid the issue.  I cannot reproduce it
here and have had 3 madexcept bug reports on this specifically

John

"Tim Young [Elevate Software]" <timyoung@elevatesoft.com> wrote in message
news:F6C90152-1E6C-4D18-B759-61A6FA9EE25B@news.elevatesoft.com...
> John,
>
> << Thanks Tim, looking forward to your further comments >>
>
> Okay, sorry about the delay.  Before you reload the BLOBs, are you
> altering the table to make the BLOB field use compression ?  Because, if
> not, then you could end up drastically increasing the size of the BLOBs on
> disk.
>
> The test I'm running here seems to work okay.  What I'm doing is initially
> populating a table's BLOB field with about 2.5GB of data.  The table has a
> BLOB block size of 32768 bytes (32KB).  Then, I'm running through the
> table with this code:
>
>      First;
>      while (not EOF) do
>         begin
>         Edit;
>         TempBlobSize:=biolifeNotes.BlobSize;
>         biolifeNotes.SaveToFile('c:\temp\dummy.txt');
>         biolifeNotes.Clear;
>
> biolifeNotes.AsString:=RandomString((TempBlobSize+Integer(TempBlobSize div
> 2)));
>         Post;
>         Label1.Caption:=biolifeSpeciesNo.AsString;
>         Label1.Update;
>         Next;
>         end;
>
> which simulates both saving the BLOB to disk, clearing the BLOB, and then
> re-populating the BLOB with a new string that is (at most) 50% larger than
> the previous size of the BLOB.  This simulates expanding the size of the
> BLOB for each record.
>
> --
> Tim Young
> Elevate Software
> www.elevatesoft.com

John,

<< I cannot reproduce it here and have had 3 madexcept bug reports on this
specifically >>

Have you tried it with exactly the same data as that used by the customer
that had the problem ?  This should be a very reproducible issue, when used
with the same data.

If you could get me the same 3.x source data that is causing the problem for
the customer, along with the code that you're using, I could tell you what
the problem is.  At this point, however, there's not much more I can look
at.

--
Tim Young
Elevate Software
www.elevatesoft.com