Microsoft SQL (MsSql) has Issues with BLOBs when Driver TRACE is Turned ON

[Bruce]

So this is unexpected enough that I thought I’d post here in case others run into the same issue.

I’ve been using build 13815 (Clarion 11.1). Between MyTable and Secwin 7, I’ve been doing a lot of work with Blobs. Blobs in MsSql, Firebird, Postgres - it’s all been going well.

A developer contacted me regarding Secwin, and blobs, because for him, blobs stopped working (completely, MsSql) after Clarion 10. He sent me an example app (works fine on my machine, but fails on his).

Today we discovered that he had TRACE turned on for the MsSql driver. He always has trace on. When we turned TRACE off though, the program worked on his machine.

So it appears that turning TRACE on can have side-effects, in this case on tables with Blobs. So if you get an issue with tables-with-blobs, try turning TRACE off.

Bet you didn’t see that coming

[totalhip]

Speed, or rather lack of, was never noticed while using with TRACE turned on?

[Bruce]

He knew TRACE was on. He uses it all the time. It has speed implications (but only on the developer machine.) So it wasn’t a surprise that it was running. It was a surprise that it caused a side-effect.

[Rick_UpperPark]

I think this is related. Clearly, there are issues with Trace and BLOBs in SQL.

Saving a Clarion Blob to Microsoft SQL - Error: Access Violation

Hi Federico, Here’s a Github link to the app: TestBlobApp/ at main · janniesoftycomp/TestBlobApp · GitHub I’ve added the MsSql driver trace and it seems the blob field is full of garbage when sending to Sql - possibly flowing over in restricted memory - cause the access violation. You can find the complete log in the “TestBlobApp.txt” file here: TestBlobApp/Gen/Bin at main · janniesoftycomp/TestBlobApp · GitHub Here’s a snippet of the suspected garbage: [image] Apologies for not replyin…

[CarlBarnes]

@Bruce

Blobs stopped working
TRACE On can have side-effects,
So if you get an issue with tables-with-blobs

Can you give some description of the “Issues”, “Side Effects” or “Not Working” ?

Does not ADD BLOBs ?
Does not PUT (update) ?
Does not GET BLOBs ?
NEXT does not get BLOBs ?

Was this TRACE turned ON using DRIVERS.INI or runtime PROP:Profile ?

[Bruce]

In this case Trace was turned on using an INI file - ie via the TRACE.exe. we did not test turning it on and off in code.

The effect was that it generated a MESSAGE error when Adding a record to the table. Basically the ADD failed, with an obscure error. Ive got the example so i can run it in the morning and post a screen shot.