Just wondering if anyone has experienced any issues with garbage collection
in .net. We developed an application using VB .NET; many of the pages made
db calls.
One of the developers forgot to close the connection(s) and DataReader
objects. We found that once the site recieved a large number of hits, the
server died on us and memory usage was ridiculously high. Since that, we've
closed all the connections and datareaders and the app works great..
Should the .NET GC not have managed all of this for us?
BTW: I know its good coding practice to close everything you open.. but just
wondering IF GC does this or not..
Bijoy
8  1178 
First of all, with datareaders, if you do not close the reader after the
usage, you can not reuse the connection on which it opened. This is not a
garbage collection issue, its a logical error. Garbage collection cleans the
resources for you, by doing automatic memory deallocation, but it doesnt
close the datareader for you. Thats your job. Also, If your application
doesnt allow database connection pooling, you need to dispose your database
connection. But, your application seems to be using the connection pooling,
so you do not have to worry. By the way, the reason you need to call dispose
on database connection is, it is unmanaged object. GC can not clean the
unmanaged resources for you
--
Kumar Reddi http://kumarreddi.blogspot.com
"Bijoy Naick" <b_*****@yahoo.ca> wrote in message
news:uT**************@TK2MSFTNGP09.phx.gbl... Just wondering if anyone has experienced any issues with garbage
collection in .net. We developed an application using VB .NET; many of the pages made
db calls.
One of the developers forgot to close the connection(s) and DataReader
objects. We found that once the site recieved a large number of hits, the
server died on us and memory usage was ridiculously high. Since that,
we've closed all the connections and datareaders and the app works great..
Should the .NET GC not have managed all of this for us?
BTW: I know its good coding practice to close everything you open.. but
just wondering IF GC does this or not..
Bijoy
Understood.. so what happens in the following case..
Assume that I have a custom class - call it Events. One of the methods of
this class is GetEvents defined/implemented as follows:
public function GetEvents(startDate, endDate) as sqlDataReader
Dim myReader As SqlDataReader
Dim oConn As SqlConnection
oConn.Open()
sql = "select * from events in date range"
myReader = oConn.ExecuteReader(sql)
oConn.Close()
return myReader
end function
If an aspx page creates an instance of the Events class and calls the
GetEvents method, it will get a reader back.. How can I close the reader
defined in the GetEvents method?
BTW: I took a look at the code in the Application Block provided by Msft
called SqlHelper. Their code doesnt close the reader either..
Bijoy
"Kumar Reddi" <Ku********@REMOVETHIS.gmail.com> wrote in message
news:OR**************@TK2MSFTNGP15.phx.gbl...
First of all, with datareaders, if you do not close the reader after the
usage, you can not reuse the connection on which it opened. This is not a
garbage collection issue, its a logical error. Garbage collection cleans
the resources for you, by doing automatic memory deallocation, but it doesnt
close the datareader for you. Thats your job. Also, If your application
doesnt allow database connection pooling, you need to dispose your
database connection. But, your application seems to be using the connection
pooling, so you do not have to worry. By the way, the reason you need to call
dispose on database connection is, it is unmanaged object. GC can not clean the
unmanaged resources for you
--
Kumar Reddi
http://kumarreddi.blogspot.com
"Bijoy Naick" <b_*****@yahoo.ca> wrote in message
news:uT**************@TK2MSFTNGP09.phx.gbl... Just wondering if anyone has experienced any issues with garbage
collection in .net. We developed an application using VB .NET; many of the pages
made db calls.
One of the developers forgot to close the connection(s) and DataReader
objects. We found that once the site recieved a large number of hits,
the server died on us and memory usage was ridiculously high. Since that,
we've closed all the connections and datareaders and the app works great..
Should the .NET GC not have managed all of this for us?
BTW: I know its good coding practice to close everything you open.. but
just wondering IF GC does this or not..
Bijoy
You can not return reader after the connection is closed. Yes, Close()
method does close all the readers associated with the connections. Though
microsoft documentation does not say anything about it.
But to return a dataReader you need to keep the connection open. So, you
might be wondering how you are going to close the connection in the another
method. For this, you should create the dataReader using
ExecuteReader(CommandBehavior.CloseConnection);
so your reader should be created as
sql.ExecuteReader(CommandBehavior.CloseConnection) ;
Creating reader this way, would close the database connection associated
with the reader, when the reader itself is closed.
So, in your calling function, simply close the reader after you are done
with it. That would close the connection as well
--
Kumar Reddi http://kumarreddi.blogspot.com
"Bijoy Naick" <b_*****@yahoo.ca> wrote in message
news:uw**************@TK2MSFTNGP14.phx.gbl... Understood.. so what happens in the following case..
Assume that I have a custom class - call it Events. One of the methods of
this class is GetEvents defined/implemented as follows:
public function GetEvents(startDate, endDate) as sqlDataReader
Dim myReader As SqlDataReader
Dim oConn As SqlConnection
oConn.Open()
sql = "select * from events in date range"
myReader = oConn.ExecuteReader(sql)
oConn.Close()
return myReader
end function
If an aspx page creates an instance of the Events class and calls the
GetEvents method, it will get a reader back.. How can I close the reader
defined in the GetEvents method?
BTW: I took a look at the code in the Application Block provided by Msft
called SqlHelper. Their code doesnt close the reader either..
Bijoy
"Kumar Reddi" <Ku********@REMOVETHIS.gmail.com> wrote in message
news:OR**************@TK2MSFTNGP15.phx.gbl...
First of all, with datareaders, if you do not close the reader after the
usage, you can not reuse the connection on which it opened. This is not
a garbage collection issue, its a logical error. Garbage collection cleans
the resources for you, by doing automatic memory deallocation, but it doesnt
close the datareader for you. Thats your job. Also, If your application
doesnt allow database connection pooling, you need to dispose your
database connection. But, your application seems to be using the connection
pooling, so you do not have to worry. By the way, the reason you need to call
dispose on database connection is, it is unmanaged object. GC can not clean the
unmanaged resources for you
--
Kumar Reddi
http://kumarreddi.blogspot.com
"Bijoy Naick" <b_*****@yahoo.ca> wrote in message
news:uT**************@TK2MSFTNGP09.phx.gbl... Just wondering if anyone has experienced any issues with garbage
collection in .net. We developed an application using VB .NET; many of the pages made db calls.
One of the developers forgot to close the connection(s) and DataReader
objects. We found that once the site recieved a large number of hits, the server died on us and memory usage was ridiculously high. Since that,
we've closed all the connections and datareaders and the app works great..
Should the .NET GC not have managed all of this for us?
BTW: I know its good coding practice to close everything you open..
but just wondering IF GC does this or not..
Bijoy
In this case you are handing ownership of the SqlDataReader over to
the caller of the method. After all, only the caller knows when they
are done with the reader and are ready to close it.
There is no ExecuteReader method on SqlConnection in 1.1. Is this 2.0
or a custom library?
The best practice when returning a SqlDataReader from a method is to
use:
= command.ExecuteReader(CommandBehavior.CloseConnect ion)
The above ensures that the underlying database connection is closed
when the SqlDataReader is closed.
--
Scott http://www.OdeToCode.com/blogs/scott/
On Tue, 14 Dec 2004 15:15:23 -0500, "Bijoy Naick" <b_*****@yahoo.ca>
wrote: Understood.. so what happens in the following case..
Assume that I have a custom class - call it Events. One of the methods of
this class is GetEvents defined/implemented as follows:
public function GetEvents(startDate, endDate) as sqlDataReader
Dim myReader As SqlDataReader
Dim oConn As SqlConnection
oConn.Open()
sql = "select * from events in date range"
myReader = oConn.ExecuteReader(sql)
oConn.Close()
return myReader
end function
If an aspx page creates an instance of the Events class and calls the
GetEvents method, it will get a reader back.. How can I close the reader
defined in the GetEvents method?
BTW: I took a look at the code in the Application Block provided by Msft
called SqlHelper. Their code doesnt close the reader either..
Bijoy
"Kumar Reddi" <Ku********@REMOVETHIS.gmail.com> wrote in message
news:OR**************@TK2MSFTNGP15.phx.gbl...
First of all, with datareaders, if you do not close the reader after the
usage, you can not reuse the connection on which it opened. This is not a
garbage collection issue, its a logical error. Garbage collection cleans
the resources for you, by doing automatic memory deallocation, but it doesnt
close the datareader for you. Thats your job. Also, If your application
doesnt allow database connection pooling, you need to dispose your
database connection. But, your application seems to be using the connection
pooling, so you do not have to worry. By the way, the reason you need to call
dispose on database connection is, it is unmanaged object. GC can not clean the
unmanaged resources for you
--
Kumar Reddi
http://kumarreddi.blogspot.com
"Bijoy Naick" <b_*****@yahoo.ca> wrote in message
news:uT**************@TK2MSFTNGP09.phx.gbl... > Just wondering if anyone has experienced any issues with garbage
collection > in .net. We developed an application using VB .NET; many of the pagesmade > db calls.
>
> One of the developers forgot to close the connection(s) and DataReader
> objects. We found that once the site recieved a large number of hits,the > server died on us and memory usage was ridiculously high. Since that,
we've > closed all the connections and datareaders and the app works great..
>
> Should the .NET GC not have managed all of this for us?
>
> BTW: I know its good coding practice to close everything you open.. but
just > wondering IF GC does this or not..
>
> Bijoy
>
>
hmm.. interesting..
so if i close the reader in the aspx page, the reader in the class will also
get closed?
"Kumar Reddi" <Ku********@REMOVETHIS.gmail.com> wrote in message
news:Ov*************@TK2MSFTNGP12.phx.gbl...
You can not return reader after the connection is closed. Yes, Close()
method does close all the readers associated with the connections. Though
microsoft documentation does not say anything about it.
But to return a dataReader you need to keep the connection open. So, you
might be wondering how you are going to close the connection in the
another method. For this, you should create the dataReader using
ExecuteReader(CommandBehavior.CloseConnection);
so your reader should be created as
sql.ExecuteReader(CommandBehavior.CloseConnection) ;
Creating reader this way, would close the database connection associated
with the reader, when the reader itself is closed.
So, in your calling function, simply close the reader after you are done
with it. That would close the connection as well
--
Kumar Reddi
http://kumarreddi.blogspot.com
"Bijoy Naick" <b_*****@yahoo.ca> wrote in message
news:uw**************@TK2MSFTNGP14.phx.gbl... Understood.. so what happens in the following case..
Assume that I have a custom class - call it Events. One of the methods
of this class is GetEvents defined/implemented as follows:
public function GetEvents(startDate, endDate) as sqlDataReader
Dim myReader As SqlDataReader
Dim oConn As SqlConnection
oConn.Open()
sql = "select * from events in date range"
myReader = oConn.ExecuteReader(sql)
oConn.Close()
return myReader
end function
If an aspx page creates an instance of the Events class and calls the
GetEvents method, it will get a reader back.. How can I close the reader
defined in the GetEvents method?
BTW: I took a look at the code in the Application Block provided by Msft
called SqlHelper. Their code doesnt close the reader either..
Bijoy
"Kumar Reddi" <Ku********@REMOVETHIS.gmail.com> wrote in message
news:OR**************@TK2MSFTNGP15.phx.gbl...
First of all, with datareaders, if you do not close the reader after
the usage, you can not reuse the connection on which it opened. This is
not a garbage collection issue, its a logical error. Garbage collection
cleans the resources for you, by doing automatic memory deallocation, but it
doesnt close the datareader for you. Thats your job. Also, If your
application doesnt allow database connection pooling, you need to dispose your
database connection. But, your application seems to be using the connection
pooling, so you do not have to worry. By the way, the reason you need to call
dispose on database connection is, it is unmanaged object. GC can not clean
the unmanaged resources for you
--
Kumar Reddi
http://kumarreddi.blogspot.com
"Bijoy Naick" <b_*****@yahoo.ca> wrote in message
news:uT**************@TK2MSFTNGP09.phx.gbl...
> Just wondering if anyone has experienced any issues with garbage
collection
> in .net. We developed an application using VB .NET; many of the
pages made > db calls.
>
> One of the developers forgot to close the connection(s) and
DataReader > objects. We found that once the site recieved a large number of
hits, the > server died on us and memory usage was ridiculously high. Since
that, we've
> closed all the connections and datareaders and the app works great..
>
> Should the .NET GC not have managed all of this for us?
>
> BTW: I know its good coding practice to close everything you open..
but just
> wondering IF GC does this or not..
>
> Bijoy
>
>
Yeah I noticed that Bijoy Naick was creating a datareader on the connection
object. I thought its a mistake while typing.
Hmm, so there is a ExecuteReader in .net 2.0 on connection object.
Interesting..
--
Kumar Reddi http://kumarreddi.blogspot.com
"Scott Allen" <bitmask@[nospam].fred.net> wrote in message
news:o3********************************@4ax.com... In this case you are handing ownership of the SqlDataReader over to
the caller of the method. After all, only the caller knows when they
are done with the reader and are ready to close it.
There is no ExecuteReader method on SqlConnection in 1.1. Is this 2.0
or a custom library?
The best practice when returning a SqlDataReader from a method is to
use:
= command.ExecuteReader(CommandBehavior.CloseConnect ion)
The above ensures that the underlying database connection is closed
when the SqlDataReader is closed.
--
Scott
http://www.OdeToCode.com/blogs/scott/
On Tue, 14 Dec 2004 15:15:23 -0500, "Bijoy Naick" <b_*****@yahoo.ca>
wrote:
Understood.. so what happens in the following case..
Assume that I have a custom class - call it Events. One of the methods of
this class is GetEvents defined/implemented as follows:
public function GetEvents(startDate, endDate) as sqlDataReader
Dim myReader As SqlDataReader
Dim oConn As SqlConnection
oConn.Open()
sql = "select * from events in date range"
myReader = oConn.ExecuteReader(sql)
oConn.Close()
return myReader
end function
If an aspx page creates an instance of the Events class and calls the
GetEvents method, it will get a reader back.. How can I close the reader
defined in the GetEvents method?
BTW: I took a look at the code in the Application Block provided by Msft
called SqlHelper. Their code doesnt close the reader either..
Bijoy
"Kumar Reddi" <Ku********@REMOVETHIS.gmail.com> wrote in message
news:OR**************@TK2MSFTNGP15.phx.gbl...
First of all, with datareaders, if you do not close the reader after
the usage, you can not reuse the connection on which it opened. This is not
a garbage collection issue, its a logical error. Garbage collection
cleansthe resources for you, by doing automatic memory deallocation, but it
doesnt close the datareader for you. Thats your job. Also, If your application
doesnt allow database connection pooling, you need to dispose your
database connection. But, your application seems to be using the connection
pooling, so you do not have to worry. By the way, the reason you need to call
dispose on database connection is, it is unmanaged object. GC can not clean the
unmanaged resources for you
--
Kumar Reddi
http://kumarreddi.blogspot.com
"Bijoy Naick" <b_*****@yahoo.ca> wrote in message
news:uT**************@TK2MSFTNGP09.phx.gbl...
> Just wondering if anyone has experienced any issues with garbage
collection
> in .net. We developed an application using VB .NET; many of the pages
made > db calls.
>
> One of the developers forgot to close the connection(s) and
DataReader > objects. We found that once the site recieved a large number of hits,
the > server died on us and memory usage was ridiculously high. Since that,
we've
> closed all the connections and datareaders and the app works great..
>
> Should the .NET GC not have managed all of this for us?
>
> BTW: I know its good coding practice to close everything you open..
but just
> wondering IF GC does this or not..
>
> Bijoy
>
>
Well, I checked and it doesn't appear to be in 2.0 either: http://msdn2.microsoft.com/library/492zc4xe.aspx
Perhaps the OP had a cut and paste error.
--
Scott http://www.OdeToCode.com/blogs/scott/
On Tue, 14 Dec 2004 15:42:53 -0500, "Kumar Reddi"
<Ku********@REMOVETHIS.gmail.com> wrote: Yeah I noticed that Bijoy Naick was creating a datareader on the connection
object. I thought its a mistake while typing.
Hmm, so there is a ExecuteReader in .net 2.0 on connection object.
Interesting..
my code was "pseudocodish".. not real code
"Scott Allen" <bitmask@[nospam].fred.net> wrote in message
news:9u********************************@4ax.com...
Well, I checked and it doesn't appear to be in 2.0 either:
http://msdn2.microsoft.com/library/492zc4xe.aspx
Perhaps the OP had a cut and paste error.
--
Scott
http://www.OdeToCode.com/blogs/scott/
On Tue, 14 Dec 2004 15:42:53 -0500, "Kumar Reddi"
<Ku********@REMOVETHIS.gmail.com> wrote:
Yeah I noticed that Bijoy Naick was creating a datareader on the
connectionobject. I thought its a mistake while typing.
Hmm, so there is a ExecuteReader in .net 2.0 on connection object.
Interesting..
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