Possible memory leak in SQLDataReader().

  • Thread starter Thread starter Ken Varn
  • Start date Start date
K

Ken Varn

I have a managed C++ application that is exhibiting a memory leak. I
isolated the leak down to a section of code that basically uses a managed
ADO.NET SQLDataReader object. The leak seems to occur on the
ExecuteReader() call. I am calling this method over and over again at
fairly rapid intervals. The Close() method of the reader is always called
when I am done with the SQLDataReader. Can someone tell me if there is a
way around this leak or if there is a fix out there?

Sample Code:

SqlCommand *SQLCmd = __gc new SqlCommand();
SqlDataReader *SQLReader;

SQLCmd->Connection = MyConnectionObject;
SQLCmd->CommandText = "sp_SelectImageEventID @nImageType = 1"; // My
stored procedure
SQLReader = SQLCmd->ExecuteReader();

if (SQLReader->HasRows)
{
// Do stuff
}

SQLReader->Close();



--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.

EmailID = varnk
Domain = Diebold.com
-----------------------------------
 
Since SqlDataReader implements IDisposable, you should call Dispose after
you are done with.
 
I tried calling Dispose() too. It still appears to be leaking memory. I
have not quite isolated the cause, but I think it may have something to do
with the fact that I switch connections fairly often as well.

--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.

EmailID = varnk
Domain = Diebold.com
-----------------------------------
Miha Markic said:
Since SqlDataReader implements IDisposable, you should call Dispose after
you are done with.
Click to expand...
 
What can I say - you should use a memory profiler to check whether there is
a real leak .

--
Miha Markic [MVP C#]
RightHand .NET consulting & development www.rthand.com
Blog: http://cs.rthand.com/blogs/blog_with_righthand/

Ken Varn said:
I tried calling Dispose() too. It still appears to be leaking memory. I
have not quite isolated the cause, but I think it may have something to do
with the fact that I switch connections fairly often as well.

--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.

EmailID = varnk
Domain = Diebold.com
-----------------------------------
Miha Markic said:
Since SqlDataReader implements IDisposable, you should call Dispose after
you are done with.

--
Miha Markic [MVP C#]
RightHand .NET consulting & development www.rthand.com
Blog: http://cs.rthand.com/blogs/blog_with_righthand/

Ken Varn said:
I have a managed C++ application that is exhibiting a memory leak. I
isolated the leak down to a section of code that basically uses a managed
ADO.NET SQLDataReader object. The leak seems to occur on the
ExecuteReader() call. I am calling this method over and over again at
fairly rapid intervals. The Close() method of the reader is always called
when I am done with the SQLDataReader. Can someone tell me if there is a
way around this leak or if there is a fix out there?

Sample Code:

SqlCommand *SQLCmd = __gc new SqlCommand();
SqlDataReader *SQLReader;

SQLCmd->Connection = MyConnectionObject;
SQLCmd->CommandText = "sp_SelectImageEventID @nImageType = 1"; // My
stored procedure
SQLReader = SQLCmd->ExecuteReader();

if (SQLReader->HasRows)
{
// Do stuff
}

SQLReader->Close();



--
-----------------------------------
Ken Varn
Senior Software Engineer
Diebold Inc.

EmailID = varnk
Domain = Diebold.com
Click to expand...
Click to expand...
Click to expand...
 
FYI, Close() calls Dispose() internally. So a call to Close is
sufficient.

You should be calling Close in a finally block. Otherwise if there is
an exception, close may be skipped.

//instantiate reader
try
{
//execute reader
}
finally
{
//close reader
}

Also if you are calling a stored procedure, you should be using a
CommandType of "CommandType.StoredProcedure", then add your parameter
via the parameters collection.

I'm a C# developer, not C++ so I can't comment on if your syntax or
usage of pointers is correct.

Michael Lang
 
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