ODBC Provider Can't retrieve blob data >32Kb

[AlexP]

Hello,

Please specify the DB, on which you tested your application: OpenEdge or MySQL?

[Brob]

I tested both. MySQL ODBC Driver works perfect now but OpenEdge ODBC Driver still has the same problem.

[AlexP]

Hello,

Unfortunately, we cannot fix the problem without reproducing it. For example, for PostgreSQL and MySQL this problem was fixed in different places. Therefore we cannot tell what exactly this problem is due to when working with OpenEdge. As I have wrote earlier, we need remote access to the server in order to reproduce and fix the problem.

[Brob]

Hi
I am setting up a vpn connection and test database for you and will email the connection details when ready.

I have some more information for you regarding Blob fields in Progress OpenEdge database which may help you.

When you create a blob field you have to specify the size in bytes which can be any size you choose.
For example when using CRATE TABLE
MyBlobField BLOB(33554432) , -- 32Mb
MyBlobField BLOB(1073741823) , -- 1gb (less 1 byte) max
MyBlobField BLOB(536870912) , -- half Gb
MyBlobField BLOB(16777216) , -- 16Mb

When I created the blob field 32Mb in size and then I can only retrieve 32Kb of data.
If I create the blob field at the exact a size of (1Gb -1 byte) then I can retrieve up to 64Kb.

I tried many different sizes when testing, some sizes give this error when trying to access the blob data.
Assertion Failure D:\Projects\Delphi\Dac\Common\Source\MemData.pas Line 8811

Hope this helps!

[AlexP]

Hello,

I have a DataDirect 7.1 OpenEdge Wire Protocol driver installed. Please provide the information required for connection to your server.

[Brob]

Hi

Did some more testing with the program you sent to me which you compiled with the fixes and this is what I found.

Originally I was creating the Blob field at 32mb which did not work. I can create the blob field at almost any size up to 15.75Mb all works OK.
If I make it bigger I have to increase the size in multiples of 15.75Mb e.g.
31.5, 47.25 , 63, 78.75, 94.5 ...... up to 992.25Mb (15.75x63). These also all seem to work ok. So 32Mb did not work because it did not divide by 15.75? I have no idea why!

If you want to look into this further for your own interest I will send connection details but I'm happy to work with this and the fix you already made!

When do you think will the fix be released?

[AlexP]

Hello,

Please provide the connection data for your server in order for us to be able to finally understand this behaviour.
The new version release is planned for September

[Brob]

Connection details sent and vpn now enabled.

[AlexP]

Hello,

We have reproduced the problem and will fix it shortly. Please don't close the VPN connection until we fix the problem.

[Brob]

OK I will leave it open until you tell me you have finished

[AlexP]

Hello,

We have fixed the problem, I have rebuilt your application and sent it to you. Please check the fix and let us know the result.

[Brob]

Test results.

The tables with blob fields created <= 15.75Mb - Now all work ok, any size.

Blob fields created > 15.75Mb in multiples of 15.75Mb all work ok.

Blob fields created > 15.75Mb when the size not in multiples of 15.75Mb only return the first 31995 bytes of data (test tables ending in _16MB, _32MB, _640MB, _1GB). These returned 0 bytes with the previous test application.

[Brob]

Hi Alex
Are you still working on this?

[AlexP]

Hello,

We have fixed the problem. From now, such fields will be mapped as BLOB by default - data and size are retrieved correctly.

[Brob]

Hi Alex

That's excellent news! Do you want me to test again?

I know you spent a lot of time on this, so many thanks for all your hard work. Another good reason to buy all your data access components from Devart!