Re: [sqlite] Handle leak using IIS on windows 7?

[Doug]

This was exactly the problem; I didn't realize the 'static' variables are
persisted between page views in ASP.Net

Adding an '_instance = null;' fixed the issue.

Thanks muchly.

Cheers,
Doug.

On Tue, Jul 19, 2011 at 11:58 AM, Joe Mistachkin wrote:

>
> After reading the code, I noticed the following:
>
> 1. From the static Dump method, an instance of the DbLogger class is
> created via the static Get method and stored in the _instance static
> variable.
>
> 2. The connection itself is opened in the constructor for the DbLogger
> class via the InitDb method.
>
> 3. Prior to returning a result, the Dump method closes the connection
> and sets the _connection instance variable to null.
>
> 4. The second time the Dump method is executed, the existing instance
> of the DbLogger class will be used (i.e. the one stored in the static
> _instance variable).
>
> 5. This existing instance of the DbLogger class no longer has a valid
> connection because it was previously closed (and set to null).
>
> 6. Newly created commands will not have a valid connection.
>
> 7. Attempting to execute a command without a valid connection will
> result in the exception you are seeing.
>
> --
> Joe Mistachkin
>
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Re: [sqlite] Handle leak using IIS on windows 7?

[Joe Mistachkin]

After reading the code, I noticed the following:

1. From the static Dump method, an instance of the DbLogger class is
created via the static Get method and stored in the _instance static
variable.

2. The connection itself is opened in the constructor for the DbLogger
class via the InitDb method.

3. Prior to returning a result, the Dump method closes the connection
and sets the _connection instance variable to null.

4. The second time the Dump method is executed, the existing instance
of the DbLogger class will be used (i.e. the one stored in the static
_instance variable).

5. This existing instance of the DbLogger class no longer has a valid
connection because it was previously closed (and set to null).

6. Newly created commands will not have a valid connection.

7. Attempting to execute a command without a valid connection will
result in the exception you are seeing.

--
Joe Mistachkin

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Re: [sqlite] Handle leak using IIS on windows 7?

[Simon Slavin]

On 19 Jul 2011, at 4:07am, Doug wrote:

> I'm pretty sure the issue is something to do with file handles. For the same
> reason after loading the page (from an IIS server) and then closing the
> page, waiting 1 minute or two and then attempting to remove the db.sqlite
> file, I get an "error, file is in use".

Remove as much as you can and see if the error disappears.  For instance, 
delete the stuff about creating and deleting the file.  Delete the stuff about 
creating the table.  In fact everything that depends on 'init'.  What about 
that INSERT ?  If you remove it does the error go away ?

Give us a ten-line toy example that still produces the error.  Then we'll be 
more likely to guess what's going on.

Simon.
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Re: [sqlite] Handle leak using IIS on windows 7?

[Doug]

ection);
sqlCmd.CommandText = cmd;

SQLiteDataReader reader = sqlCmd.ExecuteReader();

while(reader.Read())
{
var instance = new DbLoggerRecord();
int i = reader.GetOrdinal("Created");
String createdString = (string) reader.GetValue(i);
instance.Created = (DateTime) DateTime.Parse(createdString);
if (reader.GetValue(reader.GetOrdinal("Context")).GetType()
!= typeof(DBNull))
instance.Context =
(String)reader.GetValue(reader.GetOrdinal("Context"));
else
instance.Context = "NULL";
if (reader.GetValue(reader.GetOrdinal("Message")).GetType()
!= typeof(DBNull))
instance.Message = (String)
reader.GetValue(reader.GetOrdinal("Message"));
else
instance.Message = "NULL";
rtn.Add(instance);
}

return rtn;
}

public void Clear()
{
string cmd = "DELETE FROM Log";
var sqlCmd = new SQLiteCommand(_connection);
sqlCmd.CommandText = cmd;
sqlCmd.ExecuteNonQuery();
}

public void Commit()
{
if (_transaction != null)
{
_transaction.Commit();
_transaction = null;
}
}

public string HtmlFormatRecords(IEnumerable records)
{
StringBuilder b = new StringBuilder();
b.Append("DbLogger");
foreach(DbLoggerRecord record in records)
{
b.Append(String.Format("{0}:
{1}", record.Context, record.Message));
}
b.Append("");
return b.ToString();
}

public static DbLogger Get()
{
if (_instance == null)
_instance = new DbLogger();
return _instance;
}

public static string Dump()
{
var l = Get();
var rtn = l.HtmlFormatRecords(l.GetRecords(100));
l.Close(); // If we're printing, we're done for now.
return (rtn);
}
}
}





On Mon, Jul 18, 2011 at 8:09 PM, Black, Michael (IS) <michael.bla...@ngc.com
> wrote:

> If you showed a small sample code that caused your problem it would sure
> help a lot.
>
>
>
> I peeked at the library code.  That message is generated when _cnn is null
> (the DB connection).
>
>private void InitializeForReader()
>{
>  if (_activeReader != null && _activeReader.IsAlive)
>throw new InvalidOperationException("DataReader already active on
> this command");
>
>  if (_cnn == null)
>throw new InvalidOperationException("No connection associated with
> this command");
>
>
>
> It is set on a "new Connection".
>
>
>
> It is only turned to null in one place (in Commit).  But why in the world
> you would null _cnn on a commit is beyond me.
>
> Are you using a commit?  It could be autocommit I supposed causing it.
>
> I'd comment out that "_cnn = null" line below and see if it solves your
> problem.  Sure would explain why it only works once.
>
>
>
> /// 
>/// Commits the current transaction.
>/// 
>public override void Commit()
>{
>  IsValid(true);
>
>  if (_cnn._transactionLevel - 1 == 0)
>  {
>using (SQLiteCommand cmd = _cnn.CreateCommand())
>{
>  cmd.CommandText = "COMMIT";
>  cmd.ExecuteNonQuery();
>        }
>      }
>  _cnn._transactionLevel--;
>  _cnn = null;
>}
>
>
>
> Michael D. Black
>
> Senior Scientist
>
> NG Information Systems
>
> Advanced Analytics Directorate
>
>
>
> 
> From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
> behalf of Doug [douglas.lin...@gmail.com]
> Sent: Monday, July 18, 2011 1:34 AM
> To: sqlite-users@sqlite.org
> Subject: EXT :[sqlite] Handle leak using IIS on windows 7?
>
> Hi there,
>
> I've searched around and found a few threads like this:
> http://sqlite.phxsoftware.com/forums/t/2480.aspx
>
> Basically, I have the same issue.
>
> When access the sqlite database via a  website (MVC3 running on IIS) the
> first time, sqlite works fine.
>
> I properly call connections.Close() when I'm done...
>
> And the next time I try to access it I get:
> System.InvalidOperationException: No connection associated with this
> command
>
> Manually stopping the dev web server, or restarting the iis application

Re: [sqlite] Handle leak using IIS on windows 7?

[Black, Michael (IS)]

If you showed a small sample code that caused your problem it would sure help a 
lot.



I peeked at the library code.  That message is generated when _cnn is null (the 
DB connection).

private void InitializeForReader()
{
  if (_activeReader != null && _activeReader.IsAlive)
throw new InvalidOperationException("DataReader already active on this 
command");

  if (_cnn == null)
throw new InvalidOperationException("No connection associated with this 
command");



It is set on a "new Connection".



It is only turned to null in one place (in Commit).  But why in the world you 
would null _cnn on a commit is beyond me.

Are you using a commit?  It could be autocommit I supposed causing it.

I'd comment out that "_cnn = null" line below and see if it solves your 
problem.  Sure would explain why it only works once.



/// 
/// Commits the current transaction.
/// 
public override void Commit()
{
  IsValid(true);

  if (_cnn._transactionLevel - 1 == 0)
  {
using (SQLiteCommand cmd = _cnn.CreateCommand())
{
  cmd.CommandText = "COMMIT";
  cmd.ExecuteNonQuery();
}
  }
  _cnn._transactionLevel--;
  _cnn = null;
}



Michael D. Black

Senior Scientist

NG Information Systems

Advanced Analytics Directorate




From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on 
behalf of Doug [douglas.lin...@gmail.com]
Sent: Monday, July 18, 2011 1:34 AM
To: sqlite-users@sqlite.org
Subject: EXT :[sqlite] Handle leak using IIS on windows 7?

Hi there,

I've searched around and found a few threads like this:
http://sqlite.phxsoftware.com/forums/t/2480.aspx

Basically, I have the same issue.

When access the sqlite database via a  website (MVC3 running on IIS) the
first time, sqlite works fine.

I properly call connections.Close() when I'm done...

And the next time I try to access it I get:
System.InvalidOperationException: No connection associated with this command

Manually stopping the dev web server, or restarting the iis application pool
fixes this for one more page view.

It seems like the IIS config is leaving the process hanging around, and
after calling close there (I guess) must be some handle which is being kept
and keeping a reference to the database, preventing anything else from
accessing it.

Seeing as how this has happened to a few people, I was hoping someone here
had seen this before and had a solution?

I'm using the Precompiled Binaries for 32-bit Windows (.NET Framework 4.0)
from http://system.data.sqlite.org/index.html/doc/trunk/www/downloads.wiki(32
bit mode enabled on iis), but I've tried the 64-bit version with the
same result.

Cheers,
Doug.
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[sqlite] Handle leak using IIS on windows 7?

[Doug]

Hi there,

I've searched around and found a few threads like this:
http://sqlite.phxsoftware.com/forums/t/2480.aspx

Basically, I have the same issue.

When access the sqlite database via a  website (MVC3 running on IIS) the
first time, sqlite works fine.

I properly call connections.Close() when I'm done...

And the next time I try to access it I get:
System.InvalidOperationException: No connection associated with this command

Manually stopping the dev web server, or restarting the iis application pool
fixes this for one more page view.

It seems like the IIS config is leaving the process hanging around, and
after calling close there (I guess) must be some handle which is being kept
and keeping a reference to the database, preventing anything else from
accessing it.

Seeing as how this has happened to a few people, I was hoping someone here
had seen this before and had a solution?

I'm using the Precompiled Binaries for 32-bit Windows (.NET Framework 4.0)
from http://system.data.sqlite.org/index.html/doc/trunk/www/downloads.wiki(32
bit mode enabled on iis), but I've tried the 64-bit version with the
same result.

Cheers,
Doug.
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