Strange Error

  • Thread starter Thread starter Jeff
  • Start date Start date
J

Jeff

Okay, I'm still new to vb.net 2005 - throught this was a hardware problem,
but now I don't know.
(I'm having some problem with my newgroup provider, so hopefully this will
go through)

This problem just started about a week ago, before all was fine. I'm using
the code below to access a mysql database. On the line indicated when the
connection is opened, the application has been sporatically drawing an
error. It doesn't occur very often - so I don't understand what's going on.
The app reports

"Attempted to read or write protected memory. This is often an indication
that other memory is corrupt."

Okay - so perhaps a bad stick of memory - so I pulled one of the two sticks
temporarily and the problem seemed to go away. Nothing for about a week.
....but now I got the same error. I get similar errors in the event log of
the server (W2K3 IIS6).

I can't see how this has anything to do with my code since the problem is
only periodic. I don't know if it is due to the underlying visual studio,
but if I understand correctly, w3wp.exe refers to IIS. there is nothing in
any error messages referring to mysql, so I can't see that the database is
the problem.

Can anyone tell me what might be going on?

Jeff


Try
Dim MyCommand As New OdbcCommand(sb.ToString, MyConn)
MyCommand.CommandType = CommandType.Text
MyConn.Open() ' drawing the
bad memory error here also.
Dim dr As OdbcDataReader =
MyCommand.ExecuteReader(CommandBehavior.SingleRow)
Using (dr)


Event Type: Error
Event Source: COM+
Event Category: Unknown
Event ID: 4786
Date: 5/25/2007
Time: 8:45:16 PM
User: N/A
Description:
The system has called a custom component and that component has failed and
generated an exception. This indicates a problem with the custom component.
Notify the developer of this component that a failure has occurred and
provide them with the information below.
Component Prog ID: 0[ODBC][Env e6f14e8]
Method Name: IDispenserDriver::DestroyResource
Process Name: w3wp.exe
Exception: C0000005
Address: 0x7C82F583
Call Stack:
ntdll!RtlGetLastWin32Error + 0xc0
ntdll!RtlAllocateHeap + 0x58d
myodbc3!LoadByOrdinal + 0x560
myodbc3!SQLTransact + 0x9018


For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.

Event Type: Error
Event Source: Application Error
Event Category: (100)
Event ID: 1000
Date: 5/25/2007
Time: 8:45:16 PM
User: N/A
Description:
Faulting application w3wp.exe, version 6.0.3790.1830, faulting module
ntdll.dll, version 5.2.3790.1830, fault address 0x0002f583.
 
Firstly, a word of advice.

You are using Microsoft Windows Mail as your news reader so I recommend that
you connect directly to msnews.mocrosoft.com to access this and other MS
provided newsgroups. If you do then you won't have to worry about 'some
problem with your newgroup provider'.

Now to the issue at hand.

The message, "Attempted to read or write protected memory. This is often an
indication
that other memory is corrupt.", is a message associated with an
AccessViolationException which is defined as follows:

An access violation occurs in unmanaged or unsafe code
when the code attempts to read or write to memory that
has not been allocated, or to which it does not have
access. This usually occurs because a pointer has a bad
value. Not all reads or writes through bad pointers lead
to access violations, so an access violation usually
indicates that several reads or writes have occurred
through bad pointers, and that memory might be corrupted.
Thus, access violations almost always indicate serious
programming errors. In the .NET Framework version 2.0, an
AccessViolationException clearly identifies these serious
errors.

In programs consisting entirely of verifiable managed code,
all references are either valid or null, and access
violations are impossible. An AccessViolationException
occurs only when verifiable managed code interacts with
unmanaged code or with unsafe managed code.

I don't know where you got the impression that the memory chips might be at
fault but that is well wide of the mark. If your memory chips started
playing up then I suspect that you would probably not even be able to boot
the computer in question.

While the database it self might not be the problem, the ODBC driver you are
using certainly is and it certainly will contain some unmanaged code. This
is clearly indicated in the extract from the event log, so that is where you
need to start.

We can't really be of anymore help at this stage because we have no idea
what ODBC driver you are using.


Jeff said:
Okay, I'm still new to vb.net 2005 - throught this was a hardware problem,
but now I don't know.
(I'm having some problem with my newgroup provider, so hopefully this will
go through)

This problem just started about a week ago, before all was fine. I'm using
the code below to access a mysql database. On the line indicated when the
connection is opened, the application has been sporatically drawing an
error. It doesn't occur very often - so I don't understand what's going
on. The app reports

"Attempted to read or write protected memory. This is often an indication
that other memory is corrupt."

Okay - so perhaps a bad stick of memory - so I pulled one of the two
sticks temporarily and the problem seemed to go away. Nothing for about a
week. ...but now I got the same error. I get similar errors in the event
log of the server (W2K3 IIS6).

I can't see how this has anything to do with my code since the problem is
only periodic. I don't know if it is due to the underlying visual studio,
but if I understand correctly, w3wp.exe refers to IIS. there is nothing in
any error messages referring to mysql, so I can't see that the database is
the problem.

Can anyone tell me what might be going on?

Jeff


Try
Dim MyCommand As New OdbcCommand(sb.ToString, MyConn)
MyCommand.CommandType = CommandType.Text
MyConn.Open() ' drawing the
bad memory error here also.
Dim dr As OdbcDataReader =
MyCommand.ExecuteReader(CommandBehavior.SingleRow)
Using (dr)


Event Type: Error
Event Source: COM+
Event Category: Unknown
Event ID: 4786
Date: 5/25/2007
Time: 8:45:16 PM
User: N/A
Description:
The system has called a custom component and that component has failed and
generated an exception. This indicates a problem with the custom
component. Notify the developer of this component that a failure has
occurred and provide them with the information below.
Component Prog ID: 0[ODBC][Env e6f14e8]
Method Name: IDispenserDriver::DestroyResource
Process Name: w3wp.exe
Exception: C0000005
Address: 0x7C82F583
Call Stack:
ntdll!RtlGetLastWin32Error + 0xc0
ntdll!RtlAllocateHeap + 0x58d
myodbc3!LoadByOrdinal + 0x560
myodbc3!SQLTransact + 0x9018


For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.

Event Type: Error
Event Source: Application Error
Event Category: (100)
Event ID: 1000
Date: 5/25/2007
Time: 8:45:16 PM
User: N/A
Description:
Faulting application w3wp.exe, version 6.0.3790.1830, faulting module
ntdll.dll, version 5.2.3790.1830, fault address 0x0002f583.
Click to expand...
 
Stephany Young said:
I recommend that you connect directly to msnews.mocrosoft.com to access
this and other MS provided newsgroups.
Click to expand...

Done. Thanks
In programs consisting entirely of verifiable managed code,
all references are either valid or null, and access
violations are impossible.
Click to expand...
While the database it self might not be the problem, the ODBC driver you
are using certainly is and it certainly will contain some unmanaged code.
This is clearly indicated in the extract from the event log, so that is
where you need to start.

We can't really be of anymore help at this stage because we have no idea
what ODBC driver you are using.
Click to expand...

I believe that I have MySql 3.51.12 ODBC driver. I just checked their site
and see that they have a 3.51.15 driver out and perhaps changing might help?

I get the general idea of your helpful comments, but I'm a bit new and some
of the specifics/implications are a bit over my head.

Are you suggesting that the entire driver is written incorrectly, there
might be a bug in the particular version I have, or it is hard to tell?

Jeff
 
It's not a matter of believing if you have such annd such a driver. You
should know for absolute sure what it is. If you don't know then check!

I was suggesting nothing about their driver because I don't know anything
about it. All I was pointing out was what was recorded in the event log.
 
Stephany Young said:
It's not a matter of believing if you have such annd such a driver. You
should know for absolute sure what it is. If you don't know then check!

I was suggesting nothing about their driver because I don't know anything
about it. All I was pointing out was what was recorded in the event log.
Click to expand...


Okay then, it is most definitely mysql 3.15.12 dated 10/15/2005

I must admit that I don't do this full time and I'm largely self-taught. If
someone gets me started and I can figure out what to read I can usually go
from there. But when I see an error message that says something about memory
possibly being corrupt, I assume that this means a hardware problem. There
are memory testing programs available, but I haven't yet used the one that I
have as it would require me to take the server down for a few hours while
the thing ran, and I have people accessing it right now.

In reading more on the web, others are reporting some problems with that
driver version, but I suspect that they will report problems with all
drivers sooner or later. I'll probably update to the newest driver and see
if that solves the problem. If you or anyone can see any way that this might
be an issue caused by my code or by asp.net I would appreciate a hint to
point me in the right direction.

Jeff
 
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