Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

"Invalid BLOB handle" problem

Posted on 1997-09-03
3
Medium Priority
?
675 Views
Last Modified: 2012-06-21
I am inquiring to find out more about this error and what is causing it. I'm using Delphi 2 with BDE v3.5 under SQL Server and Windows NT. Here is the line of code which generates the exception:

  ablobstream := TBlobStream.Create(ablobfield,bmRead);

The error message generated is:
 "Invalid BLOB handle in record buffer"

I've done a lot of searching on this particular error. Many people seem to get it, but no one has really replied to say what's causing it, or how to fix it.

Any help/information would be appreciated.
0
Comment
Question by:csean
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
3 Comments
 
LVL 1

Expert Comment

by:arh
ID: 1343572
 This seems to be a bug in BDE. I encountered it when i tried
to display memo field contents in a grid connected to a query.
(server is Oracle).
I found that it occurs only if TQuery.RequestLive property is
set to false, and when you scroll several pages down and one page up. Setting RequestLive to true eliminates this error,
but also significally slows scrolling through data set.
  I tried to use direct  BDE API calls to read blob data, but it did not help (so the problem is not in TBlobStream).
  I don't know how this bug affect data sets which are tables (not queries) because I don't use TTable at all.
  Have anyone tried to submit this as a bug report to Borland?
(they say you can do it at www.borland.com)
0
 
LVL 1

Accepted Solution

by:
arh earned 140 total points
ID: 1343573
I have found and (incomplete) answer on Borland web page.
It appears that for non-live cursors the number of accessed BLOBS is limited by BDE cache size, which can be adjusted in BDE 4.0.
Here is Borland answer:

Q: "Invalid BLOb handle" error: What is the cause and how do I fix this error?

A: If the error occurs on a non-live (dead, canned) query or a table with no indexes, then increasing the new BDE4.0 configuration parameter 'BLOBS TO CACHE' will fix the problem. This setting determines how many BLObs will be cached on the client. Applications that deal with fetching dead BLObs using dead table opens or queries can set a limit on the number of BLObs to cache depending on the resource available on the client. Setting a value 100 means the application can work with a maximum of 100 BLOb records cached. Fetching more than 100, then scrolling back 100 records results in an "Invalid BLOb handle in record buffer" error message.
NOTE: This parameter does not apply to live table opens.
0
 

Author Comment

by:csean
ID: 1343574
Thanks arh,

Your proposed answer fixed the problem we were having. Although
we did have to increase the value to 5000 because there was
nearly that many records in the result set.


0

Featured Post

Concerto's Cloud Advisory Services

Want to avoid the missteps to gaining all the benefits of the cloud? Learn more about the different assessment options from our Cloud Advisory team.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Objective: - This article will help user in how to convert their numeric value become words. How to use 1. You can copy this code in your Unit as function 2. than you can perform your function by type this code The Code   (CODE) The Im…
Have you ever had your Delphi form/application just hanging while waiting for data to load? This is the article to read if you want to learn some things about adding threads for data loading in the background. First, I'll setup a general applica…
This course is ideal for IT System Administrators working with VMware vSphere and its associated products in their company infrastructure. This course teaches you how to install and maintain this virtualization technology to store data, prevent vuln…
In response to a need for security and privacy, and to continue fostering an environment members can turn to for support, solutions, and education, Experts Exchange has created anonymous question capabilities. This new feature is available to our Pr…
Suggested Courses

688 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question